Dear Friends,
Here is a detailed explanation to this question-
Nihit wrote:
Carnivorous mammals can endure what would otherwise be lethal levels of body heat because they have a heat-exchange network
which kept the brain from getting too hot.
(A) which kept
(B) that keeps
(C) which has kept
(D) that has been keeping
(E) having kept
If which keeps was an option would you choose it ?
Verb form; Rhetorical construction
The use of the past tense (kept) is incorrect because a current situation is discussed; the present tense (keeps) is consistent with the other verbs in the sentence. In (A) and (C), which introduces a restrictive clause. Some writers follow the convention that which can only be used for nonrestrictive clauses, but insistence on this rule is controversial, and both (A) and (C) can be rejected on other grounds.
(A) Kept is the wrong tense.
(B) Correct. The verb keeps indicates a current situation and is consistent with the other verbs in the sentence. The sentence is clear and concise.
(C) Mistaken shift in tense: In this sentence the present tense expresses a timeless general principle; in contrast, has kept indicates a more definite context and time period and suggests that the heat-exchange network may no longer have this effect.
(D) Has been keeping is the wrong tense.
(E) Having is awkward and imprecise; kept is the wrong tense.
The correct answer is B.
Concepts tested here: Tenses + Idioms• “that” is used to provide information that is needed to preserve the core meaning of the sentence, and the “comma + which” construction is used to provide extra information.
• Statements of universal fact are best conveyed through the simple present tense.
• The simple past tense is used to refer to actions that concluded in the past.
A: This answer choice incorrectly uses the simple past tense verb "kept" to refer to a statement of universal fact; remember, statements of universal fact are best conveyed through the simple present tense, and the simple past tense is used to refer to actions that concluded in the past. Further, Option A incorrectly uses "which" to refer to information that is key to the core meaning of the sentence - the fact that the heat exchange system keeps the brain from getting too hot; remember, “that” is used to provide information that is needed to preserve the core meaning of the sentence, and the “comma + which” construction is used to provide extra information.
B: Correct. This answer choice correctly uses the simple present tense verb "keeps" to refer to a statement of universal fact. Further, Option B correctly uses "that" to refer to information that is key to the core meaning of the sentence - the fact that the heat exchange system keeps the brain from getting too hot.
C: This answer choice incorrectly uses the present perfect tense verb "has kept" to refer to a statement of universal fact; remember, statements of universal fact are best conveyed through the simple present tense, and the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present. Further, Option C incorrectly uses "which" to refer to information that is key to the core meaning of the sentence - the fact that the heat exchange system keeps the brain from getting too hot; remember, “that” is used to provide information that is needed to preserve the core meaning of the sentence, and the “comma + which” construction is used to provide extra information.
D: This answer choice incorrectly uses the present perfect continuous tense verb "has been keeping" to refer to a statement of universal fact; remember, statements of universal fact are best conveyed through the simple present tense, and the present perfect continuous tense (marked by "has/have been") is the correct tense to refer to actions that started in past and continue into the present.
E: This answer choice incorrectly uses the present participle ("verb+ing") phrase "having kept" to refer to a statement of universal fact; remember, statements of universal fact are best conveyed through the simple present tense.
Hence, B is the best answer choice.To understand the concept of "Simple Tenses", you may want to watch the following video (~2 minutes):
To understand the concept of "Present Perfect Continuous Tense" on GMAT, you may want to watch the following video (~1 minute):
To understand the concept of "Which" vs "That" on GMAT, you may want to watch the following video (~2 minutes):
All the best!
Experts' Global Team