SAT Sentence Completion Practice Question 25: Answer and Explanation

Next steps

Question: 25

10. In many cases, the formerly ------- origins of diseases have now been identified through modern scientific echniques.

A. insightful
B. mysterious
C. cruel
D. notable
E. useful

Correct Answer: B

Explanation:

Skill: Understanding the content, form, and function of sentences

Explanation for Correct Answer B :

Choice (B) is correct. "Mysterious" means unexplained. If one were to insert this term into the text, the sentence would read "In many cases, the formerly mysterious origins of diseases have now been identified through modern scientific techniques." The assertion that the origins of many diseases "have now been identified" indicates that they were "formerly" unknown, or "mysterious."

Explanation for Incorrect Answer A :

Choice (A) is incorrect. "Insightful" means perceptive. If one were to insert this term into the text, the sentence would read "In many cases, the formerly insightful origins of diseases have now been identified through modern scientific techniques." "Insightful" does not logically complete the sentence because it does not contrast with the meaning of the term "identified."

Explanation for Incorrect Answer C :

Choice (C) is incorrect. "Cruel" means causing pain or suffering. If one were to insert this term into the text, the sentence would read "In many cases, the formerly cruel origins of diseases have now been identified through modern scientific techniques." While the effects of illness clearly cause pain, it is illogical to claim that the origins of certain diseases are "cruel."

Explanation for Incorrect Answer D :

Choice (D) is incorrect. "Notable" means worth noticing or remarkable. If one were to insert this term into the text, the sentence would read "In many cases, the formerly notable origins of diseases have now been identified through modern scientific techniques." A fact that has only recently been discovered cannot have formerly been "notable," or remarkable.

Explanation for Incorrect Answer E :

Choice (E) is incorrect. "Useful" means having practical application. If one were to insert this term into the text, the sentence would read "In many cases, the formerly useful origins of diseases have now been identified through modern scientific techniques." The term "useful" is inappropriate in this context; the missing term must indicate that recent discoveries about the origins of certain disease were "formerly" unknown.

Previous       Next