Carnivorous mammals can endure what would otherwise be lethal levels

Dear Friends,

Here is a detailed explanation to this question-

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

This is a question that tests knowledge of restrictive vs. non-restrictive clauses.

Check this link out...Know this stuff cold...like in your sleep

https://grammartips.homestead.com/nonres ... ommas.html

Hope it helps....

@ ChrisLele: please explain the which vs that point again. I remember something about using "that" for a restrictive clause and "which" for everything else. So "that" should be used for referring to something specific and removing the part of the sentence following "that" will change its meaning. However, "which" is used for an unrestrictive clause and can refer to anything in general and removing the phrase following "which" wont change the meaning. In a sense, "Which" is used to state qualities or qualifiers.
eg. Trips that take longer than 2 hours are discouraged by the office. Vs. Trips, which can take as long as ten hours, are discouraged by the office. Is this correct?
vs

To my understanding, The basic difference b/w usage of "Which and that" is ,
Which is used with non essential Modifiers, for instance, This Car, which is painted red, is mine,

where as

That is used with a essential modifiers, for instance, The car that is painted red is mine.

Here in the question usage of That is justifiable based on the above mention rule.

Thanks

Use THAT when you are restricting the scope of what you're talking about.
Use WHICH when you define, or generally describe what you're talking about.

In this case, the sentence is describing a particular type of heat-exchange network so you use THAT.

More details here:



[youtube]https://www.youtube.com/watch?v=Re2R0cCIZ9U[/youtube]

The explanation for Q10 in the official guide suggests that the GMAT prefers "that" for use with a restrictive clause, but mentions that insistence on the rule is controversial. I've also seen other official questions in which "which" was used with a restrictive clause (without the comma).

But I doubt that the GMAT would include "that" and "which" in future questions with no other grounds to choose between them.

Agreed - I would be surprised to see the GMAT continue with a problem like this on the real test.

It may be helpful for the forum to see some of your OG examples of "which" in restrictive uses without the comma. Can you share those?

KW

In q10 of the OG, note that two options use which. Both the options make crucial tense errors.

Similarly, in Q92 of the Verbal Review (second edition), three options use which with a restrictive clause. Those options contain crucial errors (missing a definite article, using cycles to refer to the life cycle of a single parasite, ambiguous pronoun references). The explanation doesn't call out the use of which with a restrictive clause. If it had been an important distinction, they would have mentioned it.

It's possible that the explanations aren't written by the same team that framed the questions. But even so, the inclusion of which without the comma in three of the five options suggests (to me, anyway) that the GMAT doesn't seem to consider the distinction important. I am fairly certain that the GMAT won't make this the primary error in any question.

If it does do that, then we are in trouble.

I agree...based on the "controversial" wording of the explanations I don't think we will see any "which" vs. "that" questions in the future. It is interesting that the uses of "which" with a restrictive clause (no comma) all have other fatal flaws. Perhaps that is the GMAT's way of warming people up to that new usage of "which", but I really would be surprised to see "which" used correctly with a restrictive clause. The GMAT is always changing, so only time will tell...

KW

hi experts
appreciate if further explain the "having" in E, I am confused that when "having" is correct

I have some office problems which include "having" in options.

#51 OG 16
Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are now drawing solid conclusions about how the human brain grows and how babies acquire language.
(A) Neuroscientists, having amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood, are
(B) Neuroscientists, having amassed a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are -- CORRECT
(C) Neuroscientists amassing a wealth of knowledge about the brain and its development from birth to adulthood over the past twenty years, and are
(D) Neuroscientists have amassed a wealth of knowledge over the past twenty years about the brain and its development from birth to adulthood,
(E) Neuroscientists have amassed, over the past twenty years, a wealth of knowledge about the brain and its development from birth to adulthood,


#108 OG 16
As rainfall began to decrease in the Southwest about the middle of the twelfth century, most of the Monument Valley Anasazi abandoned their homes to join other clans whose access to water was less limited.
(A) whose access to water was less limited
(B) where there was access to water that was less limited
(C) where they had less limited water access
(D) with less limitations on water access
(E) having less limitations to water access -- incorrect

desiring your help

thanks a lot
have a nice day
>_~

"Having" is not the issue in either of the examples you mentioned.

The first is an example of perfect participle: having + past participle: this structure is used to indicate a completed action. The base verb here is "amass", not "have".
Having done my home work, I went to play... correct.


The second example uses "having" directly as a present participle modifier. The base verb is "have". The usage of present participle to refer to a noun touching it is NOT wrong. Option E is not wrong because of the use of "having" - it is wrong because of the faulty use of "water access", which may mean "access by water" rather than "access to water".

First Glance

The short underline features different forms of the verb keep. This problem must be testing verbs.

Issues

(1) Verb: kept; has kept; has been keeping

The changing verb tense at the end of the short underline is a big clue. When did the heat exchange network keep the brain from getting too hot?

In order to decide which verb tense or tenses are correct, you need to understand the meaning of the sentence. Mammals can endure the high body heat because they have a special characteristic.

Note that can and have are in the present tense. Unless there is a meaning-based reason to switch tenses (and here there isn't), keep should also be in the present tense. The mammals have a special characteristic that allows them (now, in the present) to stay cool. Eliminate answers (A), (C), (D), and (E).

The Correct Answer

Correct answers (B) uses the present tense verb keeps, which is consistent with have.

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

Endure meaning : suffer (something painful or difficult) patiently.

That without comma is used for essential modifiers while WHICH WITH COMMA is used for non - essential modifiers.

Also we are talking about a general concept so it must be in Simple present tense.

"That keeps" seems to be most suitable answer for this question.

Answer B

If we understand tenses somewhat well, it’ll be easy to get to the right answer in this question.

What we need here is the present tense of the word ‘keep’ and not the past tense.

With this tip, we can eliminate Options A, C and E.

Option D uses the wrong tense here and does not align with the tense in the sentence. Eliminate.

Option B alone has the right tense form.

Another tip to keep in mind when GMAT tests you on ‘which’ – there will be a comma before which to indicate the noun that it is modifying.
But there can be exceptions to this case. So, it’s better to keep this at the back of your mind to test the right answer.

Option B is the best choice.

Hope this helps!

OFFICIAL GMAT EXPLANATION

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.

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 X

We need the restrictive modifier ‘that’ here because we are focused on a specific heat exchange network…the one that keeps the brain from getting too hot

(B) that keeps CORRECT

(C) which has kept X

We need the restrictive modifier ‘that’ here because we are focused on a specific heat exchange network…the one that keeps the brain from getting too hot. The present perfect ‘has kept’ is wrong because we are referring to a characteristic/trait of the network

(D) that has been keeping X

The present perfect continuous is incorrect…

(E) having kept X

-ING modifier is wrong

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.