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Sentence Completions

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. 

Cover up your answer choices and carefully read the sentence.  Predict a word for the easier blank and eliminate any answer choices that do not match your prediction.  Then do the same with the other blank and the remaining 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.

Start with the blank that is easier for you, even if it is the second blank.  In this case the second blank is easy to predict if you take into account the information in the sentence.  If the explosive in the factory blows up the entire factory, it can detonate without warning.  Predict the word “able” and look down at your answer choices.

(A) dormant . . ready
(B) fickle . . unlikely
(C) volatile . . liable
(D) unprecedented . . intended
(E) inactive . . designed

(A)  Does “ready” mean “able?”  If someone is ready to something, that usually means that they are able to.  Hang onto this one if you are not sure that you can eliminate it.  (B)  “Unlikely” does not mean “able.”  You were just given an example of when something exploded, so it seems pretty likely that the explosive will blow up.  Eliminate this choice.  (C) The word “liable” has two meanings.  Most people know that it means “legally responsible.”  However, words can change meaning over centuries.  If you are liable for something, people can sue you if something bad happens connected with that liability.  It eventually became acceptable to use the word “liable” whenever something bad was likely to happen.  Ex: In an economic downturn people are liable to become stressed.  A factory blowing up is an unfavorable outcome, so keep this answer choice.  (D) The word “intended” has to do not with what actually happened, but what someone planned to happen.  Nobel did not plan for his own factory to blow up; he only discovered that it could.  Eliminate this choice.  (E)  “Designed” and “intended” can be used as synonyms.  No one designed this explosive to blow up the factory; Nobel just accidentally discovered that it could.  Eliminate this answer choice. 

Now turn your attention to the the first blank in the sentence.  Now that you have thought about the sentence while checking the other blank, you probably understand that Nobel was surprised by his discovery.  He did not know the explosive was so likely to blow up until his entire factory was gone.  It is okay to use a phrase as your prediction.  Predict that he discovered the explosive was “capable of exploding,” and look down at your remaining answer choices.

(A) dormant . . ready
(C) volatile . . liable

(A)  The Latin root “dorm” means “sleep.”  An explosive is active, not “sleepy” or “inactive.”  Eliminate this choice.  (C)  The Latin root “vol” means “fly.”  An explosion definitely sends things flying.  Think of a volcano that sends fire up into the air very suddenly.  Keep this choice.

The correct answer is (C).

Words used in this SC:
Detonate: to explode suddenly and violently
Dormant: inactive, as if asleep
Fickle: quick to change, not loyal
Volatile: explosive
Liable: likely to do something or susceptible to something, prone to
Unprecedented: never before seen or done
Intended: planned
Inactive: not functioning or passive
Designed: intended or planned


On sat.collegeboard.org, 60% of the responses were correct.

For more help with SAT vocabulary, visit www.myknowsys.com!