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ACT Science

SAT Question of the Day

The SAT question of the day is an Identifying Sentence Errors Question that has already been addressed on this blog: click here to see an explanation.


ACT Science Question of the Day

Science Questions on the ACT are not about memorizing facts, they are about finding information and being able to read charts.  They do not require you to know anything that is not given to you!

Passage II
    The Sun's path from sunrise to sunset varies with the time of year. A student performed the following experiments on three clear, sunny days at three- or four-month intervals throughout the course of a year to study the path of the Sun through the sky.

Experiment 1
    At a chosen Northern Hemisphere location, the student placed a stick vertically into the ground so that 1 meter of its length was left above ground. The student knew that the length of the shadow was related to the height of the Sun above the horizon and that the shadow would point away from the direction of the Sun. The length in meters (m) and direction of the shadow cast by the stick were measured one hour after sunrise (Shadow A), at mid-morning (B), at noon (C), at mid-afternoon (D), and one hour before sunset (E) on each of the three days. The direction of each shadow was determined by placing a magnetic compass at the base of the stick and aligning the north arrow with the north mark on the compass. The direction of each shadow was then determined by a comparison with the compass face markings. The results are recorded in Table 1.

Table 1
Shadow
Day 1
Day 2
Day 3
Length
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
A
5.0
SW
8.6
NW
6.8
W
B
1.2
W
2.9
NNW
1.7
NW
C
0.3
N
2.3
N
0.9
N
D
1.2
E
3.0
NNE
1.8
NE
E
5.0
SE
8.6
NE
6.9
E

Experiment 2
    The following year, the student repeated Experiment 1 at a chosen location in the Southern Hemisphere. The results are in Table 2.

Table 2
Shadow
Day 1
Day 2
Day 3
Length
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
A
9.0
SW
5.0
NW
6.9
W
B
3.2
SSW
1.1
W
1.8
SW
C
2.5
S
0.3
S
1.0
S
D
3.2
SSE
1.1
E
1.8
SE
E
9.1
SE
5.0
NE
6.9
E

When the Sun is at an altitude 45° above the horizon, a vertical object will cast a shadow with a length equal to the object’s height. Which of the following days included a measurement taken when the Sun was at an altitude of 45°?

The first paragraph under Experiment 1 tells you that the stick (the vertical object) has 1 meter above the ground.  You must find a shadow length that is equal to the height in order to know that the Sun was at an altitude of 45° at that moment.  Check the charts.  There is only one shadow that is 1 meter long.  It is in the second chart (Experiment 2) under Day 3, Shadow C.  Circle it and look down at your answer choices.

A. Day 1 in Experiment 1
B. Day 1 in Experiment 2
C. Day 2 in Experiment 1
D. Day 3 in Experiment 2

The correct answer is (D).


For the ACT Question of the Day, visit http://www.act.org/qotd/.

To get help preparing for the SAT, PSAT, or ACT Exam, visit www.myknowsys.com!

ACT Science

SAT Question of the Day

The SAT question of the day is a Sentence Completion Question that has already been addressed on this blog: click here to see an explanation.

ACT Question of the Day

The ACT contains a science section that is not on the SAT.  However, you do not have to memorize science information to do well on this test!  All you have to do is be able to logically analyze and evaluate the information that you are given.  Even if you are only preparing for the SAT right now, take a look at this science question and consider whether your strengths are suited to the ACT.

Note:  ACT science passages throw a lot of information at you.  It is best to ignore the details in the charts until you know what information the question asks you to find.
Passage II
    The Sun's path from sunrise to sunset varies with the time of year. A student performed the following experiments on three clear, sunny days at three- or four-month intervals throughout the course of a year to study the path of the Sun through the sky.

Experiment 1
    At a chosen Northern Hemisphere location, the student placed a stick vertically into the ground so that 1 meter of its length was left above ground. The student knew that the length of the shadow was related to the height of the Sun above the horizon and that the shadow would point away from the direction of the Sun. The length in meters (m) and direction of the shadow cast by the stick were measured one hour after sunrise (Shadow A), at mid-morning (B), at noon (C), at mid-afternoon (D), and one hour before sunset (E) on each of the three days. The direction of each shadow was determined by placing a magnetic compass at the base of the stick and aligning the north arrow with the north mark on the compass. The direction of each shadow was then determined by a comparison with the compass face markings. The results are recorded in Table 1.

Table 1
Shadow
Day 1
Day 2
Day 3
Length
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
A
5.0
SW
8.6
NW
6.8
W
B
1.2
W
2.9
NNW
1.7
NW
C
0.3
N
2.3
N
0.9
N
D
1.2
E
3.0
NNE
1.8
NE
E
5.0
SE
8.6
NE
6.9
E

Experiment 2
    The following year, the student repeated Experiment 1 at a chosen location in the Southern Hemisphere. The results are in Table 2.

Table 2
Shadow
Day 1
Day 2
Day 3
Length
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
Length 
(m)
Shadow 
direction
A
9.0
SW
5.0
NW
6.9
W
B
3.2
SSW
1.1
W
1.8
SW
C
2.5
S
0.3
S
1.0
S
D
3.2
SSE
1.1
E
1.8
SE
E
9.1
SE
5.0
NE
6.9
E

If the experiments were repeated after pounding the stick farther into the ground so that only 0.5 m was exposed, how would this affect the shadow lengths?

You are given a lot of information that you do not need to know to answer this question.  The passage tells you that the original stick had one meter exposed above the ground.  If you pound it in until .5 meters are exposed, you have taken half of the stick away.  Smaller things logically must make smaller shadows (think of a bug and a building at the same time of day), so look down at your answer choices.

A. They would be twice as long as those in the original experiments.
B. They would be one-and-one-half times as long as those in the original experiments.
C. They would be one-half as long as those in the original experiments.
D. They would be one-fourth as long as those in the original experiments.

(A)  The shadows would only get larger if more of the stick were exposed.  Eliminate this choice.
(B)  The shadows would only get larger if more of the stick were exposed.  Eliminate this choice.
(C)  This answer makes sense because if half of the original stick is showing, it must have half the shadow of the original stick as well.
(D)  Even if you carefully analyze all of the numbers in the chart, there are no important numbers that have a relationship of one-fourth.  Eliminate this choice.

The correct answer is (C).

Sentence Completions

Link of the Day

We once thought that sending a man to the moon was impossible. Well, NASA has done the impossible again. The Curiosity space rover, a mobile lab the size of a small car and weighing around a ton, landed safely on the surface of Mars last night after a completely autonomous seven-minute landing sequence. Because of the size and weight of the rover, NASA had to invent an entirely new process to get Curiosity to the planet's surface. The sequence involved an "automated flight-entry system," a supersonic parachute, and a giant jetpack NASA calls a "sky crane." Most impressive of all, the entire landing was accomplished without the help or input of any humans. There is a 14-minute communications delay between Earth and Mars, so it would be impossible to respond to any problems in time, and on top of that the Earth disappeared below the Martian horizon two minutes before Curiosity touched down. Read more about the landing here and about the mission here

8/5 Sentence Completions

Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole.

Sentence completion questions test your vocabulary and your ability to think logically.  Never look at the vocabulary in the answer choices until you have read the entire sentence carefully and predicted an answer choice for a blank.  If there are two blanks, focus on the easy blank and eliminate any choices that do not match your prediction for that blank.  Then return to the other blank, make a prediction for that blank and eliminate any remaining choices that do not fit with your prediction.

It was difficult to believe that the sophisticated piece of technology had ------- through the centuries from such ------- and rudimentary apparatus.

It is easy to fill in the blanks for this sentence if you understand all of the vocabulary.  However, even if you are unsure of a definition (or several), you can still use the Knowsys method to come up with a prediction.  Look at the first blank.  Paraphrase the sentence using the terms you know: “I can’t believe that technology like this came from something like that.”  The key to predicting the first blank is to find out what happened to technology over time.  It clearly changed from one description to another, but try to make your prediction a little more specific.  “Sophisticated” is a positive word, so it is safe to assume that technology improved over time.  Use the word “improved” as your prediction and look down at the first part of your answer choices. 

(A) developed . . an intricate
(B) resulted . . a complicated
(C) evolved . . a quaint
(D) degenerated . . an obsolescent
(E) differed . . an exotic

(A) matches.  (B) is a little awkward, but you can keep it in mind. (C) matches – “evolved” and “developed” can be synonyms. (D) can be eliminated because “degeneration” is a negative word; technology did not get worse over time.  (E) can be eliminated because “differed” is a neutral word for change and you are looking for a positive one.  Three answer choices remain, so look at the second blank. 

You know that something new came from something older and simpler.  The “simpler” part of this prediction is clearer if you know the definition of “rudimentary,” but you can eliminate all the wrong answer choices just by predicting the word “old.”  Look at the second answer choices now for the letters you have not yet eliminated.

(A) developed . . an intricate
(B) resulted . . a complicated
(C) evolved . . a quaint

(A) And (B) can be eliminated because “intricate” and “complicated” do not mean “old” and they are the opposite of “simple.”

The correct answer choice is (C).

Words tested in this SC:
Sophisticated: refined
Rudimentary: basic
Apparatus: a machine or tool
Intricate: complex
Quaint: having old-fashioned charm
Degenerated: degraded, having deteriorated
Obsolescent: becoming obsolete or antiquated
Exotic: foreign, non-native (*this is the second time in three days that this word appears in a question!)


On sat.collegeboard.org, 71% of responses were correct.

For more help with vocab, visit www.myknowsys.com!

Sentence Completions

Link of the day

Did you know that jellyfish are actually a kind of plankton? Their movements and gelatinous bodies make them seem complex but they are actually very simple creatures. They have no bones, brains, or heart and they are mostly water (98%). You can learn more about jellyfish here.

6/18 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Always start out by reading the sentence carefully and making a prediction for the blank. Four of the five answer choices are wrong, so looking at the answer choices without making a prediction will only hurt you. Read the sentence carefully and look for clues to help you predict a word for the blank. Then, look at the answer choices and choose the word that matches your prediction.

The jellyfish's slow pulsing action propels it in a graceful, seemingly _________ drift, but it's tentacles contain a poison potent enough to stun a swimming human.

Now that you have read the sentence carefully, look for clues that will help you to predict a word for the blank. You know that the "The jellyfish's slow pulsing action propels it in a graceful seemingly _________ drift". Whatever word you predict for the blank, it should be positive like the word "graceful." Now, look at what you see after the blank. "but it's tentacles contain a poison potent enough to . . ." The word "but" is key here because it changes the direction of the sentence. The jellyfish moves with a graceful pulsing action that is seemingly _______, but it's tentacle are very dangerous. You can predict that the jellyfish is "seemingly safe . . . , but . . ."Now that you have a prediction, all that's left is to select the answer choice that matches your prediction.

(A) sinister
(B) rhythmic
(C) murky
(D) harmless
(E) patient

As you can see, only (D) matches your prediction. You can see how easy it would have been to be tempted by (A) if you had not noticed the keyword "but." You also might have been tempted to pick (B) because "rhythmic" sounds like it would fit with "pulsing." That is why it is essential that you alway remember to predict before you look at the answer choices.

The correct answer choice is (B).

Words Tested in This SC:
sinister: inauspicious, ominous, unlucky
rhythmic: of or relating to rhythm
murky: hard to see through, as a fog or mist
harmless: incapable of causing harm or danger
patient: content to wait if necessary, not bothered with having to wait

on sat.collegeboard.org 72% of the responses were correct.

Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.







Parallelism

Link of the Day

Elevators have been in use since the 3rd century B.C. However, it wasn't until the mid 1800's that elevators came into common use. Before then they had been used mainly in industrial settings for moving materials. In 1853 though, Elisha Otis invented a safety brake system that would stop an elevator from falling if the support cables broke. His braking system is still used today. You can read more about the history of elevators here.

6/10 Identifying Sentence Errors


The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E. 


The introduction of elevators in hotels meant that previously undesirable rooms on the top floors, away from the bustle and noise of the street, became sought after and more expensive than the lower floorsNo error

Always read the sentence first to get a general feel for how it sounds. If something seems strange or wrong, start with the part of the sentence that caught your attention. Check that segment against what you know of standard English grammar. If nothing stands out to you, check all four underlined sections. When you find one that breaks the rules, mark it.

Does anything sound odd? If not, don't worry, just check each answer choice individually. You may notice that the sentence seems fairly long and complicated. That's a good sign that the test makers are trying to hide something and trick you. Remember that often the underlined portion will look alright on it own if you don't take the whole sentence into account.


(A) doesn't really have anything wrong with it. It is worth noting that the subject of our sentence is "The introduction of elevators" though. You can now check for subject verb agreement (in this case there is no subject verb agreement error).

(B) is also error free. "Previously" is an adverb modifying "undesirable" (which is an adjective modifying "rooms"). Both words are being used properly.

(C) may seem strange at first. Note that "away from the bustle of the noise of the street" is in-between two commas because it is a non-restrictive element. Even though it may look a little out of the ordinary, there is no error here either.

(D) seems to be fine as well however, you should notice that it is part of a comparison (because it is preceded by the word "than"). If you look back in the sentence to see what "the lower floors" are being compared to, you will see that the sentence is comparing "undesirable rooms on the top floors . . . " to ". . . the lower floors." Since that comparison doesn't make sense, (D) is the error.

The correct answer choice is (D).

On sat.collegeboard.com 34% of the responses were correct.

For more help with grammar, visit www.myknowsys.com!


Subject Verb Agreement

Link of the Day

Sharks are some of nature's most magnificent predators. They have no bones (only cartilage) and their streamlined bodies allow them to glide through the water at incredible speeds. While sharks have a sinister reputation, in reality they rarely attack people. You can learn more about sharks here.

6/4 Identifying Sentence Errors

The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E. 

For Identifying Sentence Errors questions, always read the sentence and focus on anything that sounds strange or wrong. Determine whether that part of the sentence is actually incorrect, then identify the part of the sentence that, if changed, would correct the error. Double-check that the other sections of the sentence are correct as they are and, finally, mark the correct answer on your answer sheet.

Most of the world’s sharks, living in temperate and tropical regions, though the Greenland shark lives in the cold Arctic waters, and the huge basking shark is at home in the seas around AntarcticaNo error



First, read the question carefully and listen for things that sound wrong. You might notice that B sounds a little strange. Since you see a verb -living- check the subject verb agreement. Here, the subject of the sentence is "sharks". "Living" looks like a verb but, as it is conjugated right now, it is a participle (a verb functioning as an adjective). In other words, the sentence does not have a verb. That means you need to change the word "living" to the word "live" to make sure that the sentence has both a subject and a verb. In this case you only need to spot the error however,  you should always try to predict how you could fix the sentence. This will help you to be confident in your answer.

The correct answer is B.

On sat.collegeboard.com, 69% of the responses were correct.

For more help with grammar, visit www.myknowsys.com!




Comma Splice

Link of the Day

Silk fabric was first developed in China more than 5000 years ago. There are various wild silks that are still being produced today, but most of the commercially available silk comes from carefully cultivating the pupae of the Bombyx Mori, more commonly known as the Mulberry Silk Moth. Each cocoon has about 1 kilometer of silk filament, but it takes 2500 cocoons to produce 1 pound of raw silk! You can learn more about the process of making silk here.

6/1 Improving Sentences

Part or all of the following sentence is underlined; beneath the sentence are five ways of phrasing the underlined material. Select the option that produces the best sentence. If you think the original phrasing produces a better sentence than any of the alternatives, select choice A.

On Improving Sentences questions, always remember to read the sentence and make a prediction about what changes would correct any errors you find. This prediction will help you eliminate wrong answers and quickly zero in on the correct choice.

The finest quality raw silk comes from the commonly domesticated silkworm, Bombyx moriit feeds on the leaves of the mulberry tree.

The first thing you should notice here is the comma after "Bombyx mori". Since the comma is not underlined, it must be correct. As the sentence stands right now, it is a run on sentence. Notice that "The finest quality raw silk comes from the commonly domesticated silkworm, Bombyx mori," could be a complete sentence on its own. Likewise, "it feeds on the leaves of the mulberry tree." could also be a sentence. Since we have two independent clauses joined by a comma, we have a comma splice. The way to fix this is either to add a coordinating conjunction or to change the second clause to a dependent clause (in general on the SAT try to pick dependent clauses over independent ones). We can now look at the answers and see which one matches our prediction.

(A) it feeds
(B) feeding
(C) they feed
(D) which feeds
(E) having fed

As always, we skip over (A) because we have already looked at the sentence the way it is (and decided that we need to change it). (B) will not work because the verb tense does not match (in general you should be wary of verbs ending in -ing). Answer (C) does not fix the comma splice. (D) uses the word which. Since which is a relative pronoun (which is used to begin a dependent clause) we can be confident that answer (D) works. Even if you are not familiar with the grammar rules, you can verify that (D) works by reading the second half of the sentence to yourself. "Which feeds on the leaves of the mulberry tree" is not a complete sentence so we have fixed the comma splice. (E) will not work because, just like with answer (C), the verb tense does not match.

The correct answer is (D).

On sat.collegboard.com 77% of the responses were correct.

For more help with grammar, visit www.myknowsys.com!



Subject Verb Agreement

Link of the Day

Recycling can reduce pollution, save energy, conserve natural resources, and even save you money! You can read more about recycling (and learn about government initiatives to increase recycling) here.

5/29 Identifying Sentence Errors

The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E. 

For Identifying Sentence Errors questions, always read the sentence and focus on anything that sounds strange or wrong. Determine whether that part of the sentence is actually incorrect, then identify the part of the sentence that, if changed, would correct the error. Double-check that the other sections of the sentence are correct as they are, and finally mark the correct answer on your answer sheet.


Besides conserving forest resources, recycling produces fewer pollutants than does the conventional pulping and bleaching processes that are normally used to create paper. No error


First, read the sentence carefully and try to see if anything sounds wrong to you. If you have a good ear you may notice that B sounds a little strange. In order to confirm the error look at the verb does and see what the subject is. In this case it is the "conventional pulping and bleaching processes" that the verb refers to. Since our subject is plural, the singular form of the word does does not fit in the sentence. 

Answer choice A is a participle (a verb that acts like an adjective) inside of a prepositional phrase ("Besides... resources"). It is used correctly. 

Answer choice C uses the word that and that is correct since the part of the sentence that follows is essential to the meaning of the sentence (if it could be omitted, the sentence would have used the word "which" preceded by a comma:  "…processes, which").

Answer choice D is an infinitive verb correctly used immediately after a normal conjugated verb. 

The correct answer is choice B.

on sat.collegeboard.org 78% of the responses were correct.

For more help with grammar, visit www.myknowsys.com!

Sentence Completions

Link of the Day

Tales of strange accidents abound throughout history, and one of the most famous is the case of Phineas Gage. A railroad construction accident in 1848 drove a metal spike straight through his head and left him with one of the first recorded cases of brain damage. His memory, motor skills, and speech suffered no change, but his personality was altered drastically from that day forward, leading to some of the first meaningful discoveries about the prefrontal cortex. Scientists have since concluded that the areas of Gage's brain that were damaged had to do with reasoning, decision making, and social conventions.

Critical Reading: Sentence Completions

Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole.

Remember that the answer choices on most SAT questions are there to confuse you. Out of the five listed, four of them are wrong! Look at the sentence, make a prediction without reading the answer choices, and then compare the answer choices to your prediction to find the one that matches most closely.

The accident left Tom not so much incapacitated as ------: he was left weak, but the doctors gave him reason to expect ------. 

First, look at the sentence and select the blank that will be easier to fill in. In this sentence, the second blank is easier. After an accident or injury, it is reasonable to expect recuperation or improvement in one's state of health. Look at the answer choices to see which items match this prediction.

A) enfeebled . . progression

B) inconvenienced . . deterioration

C) frustrated . . enervation

D) vindicated . . complication

E) debilitated . . recovery



First, eliminate B because deterioration is the opposite of recuperation. Enervation, similarly, would be the opposite of improvement after the injury, so eliminate C as well. Complications are generally unexpected, so D doesn't make sense either. Progression seems to make sense, but it is too vague to be correct in this sentence. Eliminate A. The answer is E.

Words tested in this SC
enfeeble: to make weak or faint
progression: moving from one thing to another
inconvenience: to bother or discomfort
deterioration: the process of growing worse
frustrated: foiled, stopped, disappointed
enervation: a loss of energy; debilitation
vindicated: evidence, facts, or statements that justify a claim or belief
complication: something that doesn't fit in with the pattern or plan
debilitated: weakened
recovery: a return to normal health


On sat.collegeboard.org, 66% of responses were correct.

Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.

Pronouns

Link of the Day

Sea stars, frequently misnamed "starfish," are fascinating creatures with no brain, no bones, and no blood. They are best known for their ability to regenerate their own limbs, and are a great example of the ability to adapt to any environment. 

5/11 Identifying Sentence Errors

The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E.

First, always read the sentence as if none of it were underlined. If something sounds strange or wrong, focus on that. Figure out which underlined part of the sentence you could change to correct that problem. Next, double-check the other underlined sections to make sure that they are correct. Finally, select the correct answer choice.

Among the most widespread of marine animals, starfish and sea urchins inhabit all seas except that of the polar regions. No error

Does anything sound strange? The last part of the sentence should because it has a problem. The word "except" is fine; it is a preposition, and it is used correctly. The same is true of "of," but look closely at the word "that." "That" is a pronoun, which means it must agree with one antecedent in the sentence. "That" refers to the word "seas," which is plural, so it might seem obvious that "that" should be the plural "those" in order to agree. However, because of the context of the sentence, "that" could still make sense. Imagine if the sentence referred to "all the books except that by Mr. Bob," or "all the jellybeans except that in Katie's stomach." The word "except" indicates a separation between the pronoun and its antecedent and creates a strange situation where the two do not actually have to agree, and, of course, this can create ambiguity. This sentence does not refer to books or jellybeans but to seas, specifically those "of the polar regions." If the seas are in both polar regions--that is, on both the northern and southern extremes of the globe--they cannot be the same sea. Since "that of the polar regions" needs to refer to multiple seas, the correct form is "those."



Look at the other answer choices before you mark this one on your answer document.

A: "Among" is a preposition that refers to three or more items or people. For only two, use "between." In this sentence, "among" refers to "marine animals." Since there are hundreds or thousands of different marine animals, "among" is correct.

B: "most widespread of" is an unusual construction that defies certain "normal" rules of grammar, but it is considered correct standard English.

C: "inhabit" is plural and present tense, referring to all the starfishes and sea urchins that live in seas and oceans all over the world. It is used correctly.

The answer is D.


On sat.collegeboard.org, 56% of responses were correct.


For more help with grammar, visit www.myknowsys.com!


Sentence Completions

Link of the Day

After realizing how dangerous his explosives were, Alfred Nobel rewrote his will to establish the five Nobel Prizes. Many were shocked and contested the will, and the plan for the Nobel Prizes underwent several changes, but eventually the first Nobel Prizes were awarded in 1901. Any Nobel Prize winner would make a great Excellent Example, so look through this website to find an example to add to your list. 

4/28 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Remember to read the sentence and look for clues before looking at the answer choices. Most of the answers are wrong, so any clues you find there will only lead you to the wrong answers. Instead, look for clues in the original sentence without looking at the answer choices at all. Make a prediction based on what the sentence says, then match that prediction to the answer choices.

When, in 1864, a factory established by Alfred Nobel to manufacture nitroglycerin blew up, the scientist discovered that the explosive was as ------ as it was powerful, ------ to detonate without warning.

Whenever you find yourself facing a two-blank sentence, don't automatically focus on the first blank first. Take a moment to determine which blank is easier. In this case, the second blank is easier to predict, so make a guess for that word first. Since one factory already blew up, it is easy to conclude that nitroglycerin is apt or likely to detonate without warning. Look in the answer choices for an option that matches.

A) dormant . . ready

B) fickle . . unlikely

C) volatile . . liable

D) unprecedented . . intended

E) inactive . . designed



Eliminate B immediately, since it is the opposite of your prediction. D and E don't make sense either, since Nobel obviously did not intend for his factory to explode. That leaves A, "ready," and C, "liable." Both of these would make sense, so move to the first blank.

When, in 1864, a factory established by Alfred Nobel to manufacture nitroglycerin blew up, the scientist discovered that the explosive was as ------ as it was powerful, ready or liable to detonate without warning.

Based on the fact that this explosion was completely unexpected, the word in the blank must convey that nitroglycerin is dangerous. There are many words that could fit, so stick with "dangerous" only as a general prediction. It probably won't be a perfect synonym for the answer. The only choices left are A and C:


A) dormant . . ready

C) volatile . . liable


"Dormant" doesn't make sense, so eliminate A.

When, in 1864, a factory established by Alfred Nobel to manufacture nitroglycerin blew up, the scientist discovered that the explosive was as volatile as it was powerful, liable to detonate without warning.

The answer is C.

Words tested in this SC
dormant: inactive, asleep, suspended
ready: inclined; apt to happen
fickle: quick to change
unlikely: not to be reasonably expected
volatile: explosive
liable: with used with "to," probable
unprecedented: never seen or done before
intended: planned
inactive: not active; not functioning or operating
designed: created according to a design or for an intended purpose


On sat.collegeboard.org, 62% of responses were correct.


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Sentence Completions

Link of the Day

Scientific hoaxes are not new. This top ten list includes frauds as early as 1726 and as recent as 2005! While there is not enough information on any of these examples to include them in an essay, a little bit more research could easily land you with a great selection of Excellent Examples. 

4/25 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Always read the sentence and make a prediction before looking at the answer choices. Simply glancing at the sentence is not enough; you must think of a word or idea that would fill the blank. Then, matching that word with the answer choices is fast and easy.

Although the scientist claimed to have made a major breakthrough in his research, the evidence he offered as proof of his assertion was ------ at best.

Clearly, the scientist wants others to believe that he has discovered something new and amazing. In order for them to believe him, he must present solid proof of his breakthrough. Without evidence to support his claim, no intellectual would believe the scientist in this sentence. The clue to look for in the sentence is the word "Although" because it indicates an opposite. Since we've established that the scientist is making a claim that needs evidence to support it, the opposite would be a lack of support or weak evidence. Lacking, shoddy, or meager might work.



Now look at the answer choices:

A) conclusive

B) indubitable

C) paltry

D) copious

E) extensive

Ask for each word, does conclusive mean shoddy? Does indubitable mean lacking or meager? Both words, in fact, mean that something is clear and decisive. Eliminate them since they are opposites of your prediction. Copious and extensive are also synonyms, meaning abundant and widespread, respectively. Both would indicate that the scientist had plenty of evidence to support his claim, so eliminate them as well. In fact, eliminating synonyms is a great strategy to limit the number of answer choices. When two words are as similar in meaning as conclusive and indubitable, for example, no sentence could clearly indicate that one is right and the other wrong. Since there can only be one correct answer, both synonyms must be wrong. The answer is C.

Words tested in this SC:
Conclusive: Proving an end to something
Indubitably: Clearly true; providing no possibility of doubt
Paltry: Meager, worthless, trifling; trashy, of little value
Copious: Profuse, abundant
Extensive: Widespread


On sat.collegeboard.com, 54% of responses were correct


Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.

Sentence Completions

Link of the Day

Have you ever wondered where mammals came from? This interactive page from the Smithsonian displays some fascinating information about how mammals evolved alongside dinosaurs and other prehistoric creatures. 

4/22 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Whenever you see a sentence completions question, the first thing you should do is put your hand on top of the answer choices before you read them. Next, read the sentence and check for clues about the missing words. Make a prediction, then look at the answer choices to see which ones match your prediction.

Ms. Fergusson's main criticism of the artist's rendering of the ancient mammal's physical appearance is that, unsupported by even a ------ of fossil evidence, the image is bound to be ------. 

The clues here are the words "unsupported" and "even." Together, they convey that there was no evidence at all, so the first blank is a word that means "a tiny bit." For example, "fragment," "speck," or "iota" could be your prediction.



Look at the answer choices to rule out options that don't match this prediction.

A) modicum . . speculative

B) particle . . supplemented

C) perusal . . substantiated

D) fabrication . . obsolete

E) recapitulation . . exhausted

Retain A and B as possibilities. C, D, and E all include first words that have nothing to do with your prediction, so eliminate them. Look at the sentence again to determine the correct answer.

Ms. Fergusson's main criticism of the artist's rendering of the ancient mammal's physical appearance is that, unsupported by even a modicum or particle of fossil evidence, the image is bound to be ------. 

There are only two choices left, speculative and supplemented. Since there is no fossil evidence, what would supplement the artist's imagination? That does not make sense. Eliminate B. Instead, the image is speculative, meaning that the artist imagined what the creature may have looked like.

Ms. Fergusson's main criticism of the artist's rendering of the ancient mammal's physical appearance is that, unsupported by even a modicum of fossil evidence, the image is bound to be speculative

Words tested in this question
Modicum: A small, modest, or trifling amount
Speculative: Based on a guess or unfounded opinion
Particle: Something with very small size; a fragment
Supplement: Something added, especially to make up for a deficiency
Perusal: The act of perusing or studying something carefully
Substantiate: To verify something by supplying evidence
Fabrication: Something fabricated; a falsehood or lie
Obsolete: No longer in use; disused or neglected
Recapitulation: A brief recitement or enumeration of the major points in a narrative, article, or book.
Exhaust: To draw out or let out the contents of something until it is empty

Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.

Sentence Completions

Link of the Day

What's the point of a clean room? They are used to keep sensitive materials or chemicals from being contaminated. Everyone who enters usually needs special garments to keep flakes of skin or strands of hair from mixing with the materials. When those special garments are worn out, labs send them to Kimberly-Clark to be recycled.In fact, the company is currently expanding their cleanroom and laboratory garment recycling initiative to include gloves. This program takes used materials from clean-room laboratories and clinics to make new plastic materials such as plastic lumber and picnic tables. Cool!

4/19 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Remember to read the sentence and make a prediction before looking at the answer choices. Looking at the choices before predicting the correct answer will cost you time and is very likely to change how you think about the question. The sentence will have clues built in to lead you to the correct answer, so rely on them instead of looking at the answer choices.

Mrs. Williams found it ironic that her twelve-year-old son, who made all A's on his report card, was so ------ at home, apparently unable to follow her most basic instructions concerning such commonsense matters as tidiness.

First, look for clues. This sentence has plenty. The boy is clearly smart, since he regularly earns good grades in school. However, when he gets home, his mother finds that he cannot (or will not) follow her instructions regarding tidiness... basically, he didn't want to clean his room. His mother found this apparent dip in intelligence ironic. The blank, then, would have a word that means the opposite of "smart," so "dense," "dull," or "slow" would work.

Mrs. Williams found it ironic that her twelve-year-old son, who made all A's on his report card, was so dense and slow at home, apparently unable to follow her most basic instructions concerning such commonsense matters as tidiness.



Next, look at the answer choices to find one that matches your prediction.

A) stubborn

B) astute

C) candid

D) obtuse

E) sullen

Someone astute would be excellent at following directions, so eliminate B. Candid simply means impartial, so eliminate it as well. Stubborn, obtuse, and sullen could all describe a boy who doesn't want to clean, but only obtuse gives the impression that his behavior makes him appear less intelligent than he is. The answer is D.

Words tested in this SC:
Stubborn: Refusing to move or change one's position; obstinate
Astute: Shrewd or crafty
Candid: Impartial; straightforward and sincere
Obtuse: Intellectually dull or dim-witted
Sullen: Having a brooding ill temper, sulky; somber or dismal


On sat.collegeboard.org, 50% of responses were correct.


Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.

Sentence Completions

Link of the Day

The Layman's Guide to Psychology provides interesting psychological explanations for all kinds of human and animal behaviors. If you choose one for your essay, be sure to include the source!

4/16 Sentence Completions

Choose the word or set of words that, when inserted into the sentence, best fits the meaning of the sentence as a whole.

Always remember the power of prediction: making an educated guess to fill in the blank before looking at the answer choices will save you time. Even when you cannot come up with a word, just a general idea or the connotation of the word will help you narrow down your answer choices that much more quickly. 

Since the explanations offered are ------ to the exposition, it would be unfair to treat them as ------ parts of the studies under consideration. 

This sentence is a little tricky to predict. Few clues are given, and some of those are confusing. What is "exposition?" How does it relate to considering studies? One work, however, might be all you need: "unfair." Since it would be unfair to treat something as something unlike it, the blanks are probably opposites. Look at the answer choices for two words that have opposite meanings.



A) tangential . . subsidiary

B) irrelevant . . superfluous

C) referable . . correspondent

D) incidental . . essential

E) crucial . . immutable

Something tangential is only partly related to an issue, and something subsidiary is added on. Irrelevant means something is not at all related to the main topic, and superfluous means that it is extra. Eliminate A and B because their meanings are too closely related. Referable means worthy of note or reference, and correspondent means conforming to or communicating with. Eliminate C because its words are unrelated. Something incidental is only loosely associated with the main subject of discussion, and something essential is necessary or of central importance. The two words in Choice D are opposite, so they might be the answer. Finally, choice E contains crucial, which means essential or decisive, and immutable, which means unchanging or unchangeable. Since these are unrelated, eliminate E.

The answer is D.


On sat.collegeboard.org, 45% of responses were correct.


Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.

Sentence Completions

Link of the Day

You may not have heard of Mary Wollstonecraft Shelley, but her inventive mind spawned one of the most well-known creatures in all of literature--Dr. Frankenstein's monster! Frankenstein's monster is a corpse that he reanimates using the power of electricity, and in 1816 electricity was a new and, to some, frightening idea. Frankenstein's monster could be an excellent example to illustrate humanity's innate fear of change and of the unknown. 

4/7 Sentence Completions

Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole.

Always follow the Knowsys Method for sentence completions: Cover the answers, read the sentence carefully, and make a prediction based on the clues given in the sentence. Match your answers to the prediction and then select the answer that is the most similar to the word you selected.

The impoverished city lacked the financial means to update its ------ electrical infrastructure.

What clues are embedded in the sentence to lead you to the right answer? Something in need of an update is archaic, outdated, or simply old. Moreover, a city that is impoverished would logically have a difficult time paying for the much-needed improvements to keep its equipment and facilities up to date. Look for an answer choice that is a synonym of "old," "outdated," and "archaic."


A) despondent

B) antiquated

C) rejuvenated

D) superlative

E) esoteric

Eliminate C immediately because something "rejuvenated" has been made young and new again; the opposite of old and archaic. Something "superlative" (D) is the best in its class, so that can go as well. You are left with "despondent," "antiquated," and "esoteric." Even if you do not know what the other words mean, you can reason that "antiquated" is very similar to the word "antique" and probably refers to something old or something that is not as useful as it used to be.

The answer is B.


On sat.collegeboard.org, 69% of responses were correct.


Need to build your SAT Vocab?  Visit www.myknowsys.com to check out the Knowsys Vocabulary Builder Program.