The difference between ‘have been trimmed’ and ‘are trimmed’ is that trimming is a one –time job and not a daily chore. An event that was done in the past and which or whose effect is still carried through the present will have to be expressed in present perfect, while daily chores will have to be verbed with just present tense. So 'have been trimmed' is the preferred expression
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(A) has a couple of subtle little problems. For starters, I don’t think the phrase “…will continue to visit game parks and see rhinoceroses…” is quite right in this case. Grammatically, it’s fine: “visit” and “see” are parallel verbs. Trouble is, that suggests that the two actions are somehow equally weighted, and not necessarily related: tourists visit game parks, and tourists see rhinos, but maybe not at the same time.

So the phrasing in (A) isn't WRONG, exactly, but it’s not ideal: the intent of the sentence is to question whether tourists will continue to visit game parks TO SEE rhinos. And we have that option in some of the other answer choices.

You could also argue that the pronoun “their” is potentially ambiguous. It could refer to the rhinos or the tourists or the poachers, and only the rhinos would make sense, since tourists and poachers rarely trim their own horns. And again, pronoun ambiguity isn’t an absolute rule (more on that in this video), but we’ll have better options in a moment.

If you wanted to be conservative, you could keep (A), but the problems in (A) will be fixed in another answer choice.


(B) includes the phrase “visit game parks to see [a rhino]…”, and that makes more sense than the parallel structure we saw in (A).

Trouble is, now the pronouns are worse. You could argue that “one” is a little bit ambiguous because it’s so far from “rhinoceroses”, but I can live with that – I don’t think it’s unclear, even if it isn’t awesome. But the “their” is definitely an issue: the nearest plurals are “game parks” and “tourists”, and neither of those are likely to have their horns trimmed. “Their” logically needs to refer to “rhinoceroses”, but that word is a long way from the pronoun now. That’s not cool.

So (B) is out.


(C) fixes all of the problems and imperfections of (A) and (B). We have “…continue to visit game parks to see rhinoceroses…”, and that’s better than the parallel version in (A). The pronoun has been completely removed, so now we have “once the animals’ horns have been trimmed” – and that’s clear as a bell.

Let’s keep (C).


(D) has the same parallelism problem as (A): “visit game parks and see rhinos” makes less sense than “visit game parks TO see rhinos.” See the explanation for (A) for more on this issue.

The GMAT also tends to frown on the use of “if” in situations like these. The GMAT seems to think that “if” can only be used for “if/then” (conditional) statements, but NOT for situations like this sentence, when the intent is just to indicate that two different alternatives are possible (e.g., visiting vs. not visiting game parks). I think that’s a silly thing for the GMAT to test, but who cares what I think?

The shorter version: if you’re given a choice between “if” and “whether” on the GMAT, then you’ll almost certainly want to choose “whether.”

So (D) is out.


The only major problem in (E) is the use of “if.” See (D) for more on that issue.

So (E) is gone, and we’re left with (C).
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Generally, present perfect indicates actions that started in the past and are still going on.

An alternative use of present perfect is for things that happened in the past but are still true or for things that have ongoing effects.

Some examples:
(1) We have visited Torino in November and found it lovely, though cold.
This doesn't mean we are still visiting, nor that it is still November. It just means that at least once, we did visit in November, and that history is still (and will forever be) true.

(2) I have attached the documents to this cover sheet.
This doesn't mean I am still stapling the papers as I write or as the sentence is read...it just means the documents are still attached.

In your OG example, "have been trimmed" should be interpreted in this way--the zoo employees may not still be trimming the horns, but the horns are still short.

I answered it in another way: The question to me is much rather whether "tourists come to the park and see rhinoceroses" or whether "tourists come to the park to see rhinoceroses". I think this answer (C) conveys the message much better and resolves the pronoun problem (their) as well.

Two step process:
Step 1:

This is good thinking. For example, "I went to the store and saw Mary" means I had no intention of seeing her and she happened to be there. "I went to the store to see Mary" means I knew Mary would be at the store and the purpose of my trip was to see her.
In our sentence the question is whether tourists will make a trip with the purpose of seeing the rhinos (not if the tourists will accidentally see rhinos). A and D - crossed off.

Step 2: As mentioned before, the pronoun "their" is a little ambiguous, as is the use of "one" in B and E. "One" needs to be much clearer. Here it could refer to "one" rhino or "one" horn. B and E - crossed off.
Answer: C

A proposal has been made to trim the horns from rhinoceroses to discourage poachers; the question is whether tourists will continue to visit game parks and see rhinoceroses after their horns are trimmed.

A) whether tourists will continue to visit game parks and see rhinoceroses after their horns are
B) whether tourists will continue to visit game parks to see one once their horns are
C) whether tourists will continue to visit game parks to see rhinoceroses once the animals' horns have been
D) if tourists will continue to visit game parks and see rhinoceroses once the animals' horns are
E) if tourists will continue to visit game parks to see one after the animals' horns have been

OA C

All:
I know that D and E can be rejected because of usage of "if"

Among A, B and C, B and A are rejected for lack of antecedents. I am not looking for the correct answer. I want to understand why "horns have been" is a correct usage. In other words, via is present perfect better than present tense ("are trimmed")


Any help is appreciated.

The proposal is still in effect (still true) from the past. Hence present perfect.

I disagree with gmat1220 with his reasoning here; sorry no-offense. AFAIK here IF is WRONG! There is no question of whether>if. That might be true in general, but I think here IF is just blatantly wrong.

As far as I understood, if is ONLY used for condition and CAN'T be used for QUESTIONS!

Experts, please let me know if you disagree with me.



Thanks for the reasoning. This clarifies the same doubt I had.

Let us make a 2/3 split on this.

If V/S Whether-

'whether' is used to indicate multiple or single possibilities

'If' is used to indicate a condition


Ex1- Roger cant decide whether to play tennis or football
Ex2- Roger will play if he is fit.

So, A,b,C remain. A and B there is some ambiguity. Choose C

The methodical steps to this issue may be:
1. This is question of deciding on a dilemma. Hence the conditional ‘if’ is irrelevant; dump D and E.
2. “To see” denotes the purpose of a visit and better than ‘and see’. Hence A is out.
3. To see “one” after “their” horns: the subject - pronoun number mismatch is too glaring.
4. C is the remainder
IMO, the difference in the use of present perfect or present tense is rather too thin. Both are acceptable in formal writing I suppose. As in this case: - I wonder whether I can enjoy bones once my teeth are broken - is as good as - I wonder whether I can enjoy bones once my teeth have been broken - nothing much to choose from. But this is just my feeling.
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A proposal has been made to trim the horns from rhinoceroses to discourage poachers; the question is whether tourists will continue to visit game parks and see rhinoceroses after their horns are trimmed.


I know I will get it right most of the times, since their to me seems awkward, but if I go by what I learnt in e-gmat lectures, ambiguity of pronouns can be checked by indentifying the intended meaning. So whats the exception here? their horns so their can refer only to horns.

You're right about the horns part. However, the ambiguity here is not whether the reference is to horns but whose horns. Are the tourists or the rhinoceroses having horns removed?

It seems obvious given what we know about tourists and rhinos generally, but it's not clear from the structure of the sentence.

Hi there,

Thanks for posting your query here.

As the previous poster has pointed out, 'their' does not refer to 'horns', but to either tourists or rhinoceroses. Although common sense may tell us that the rhinoceroses are more likely to have horns than the tourists are, the sentence should contain no ambiguity.

Also, note that when a pronoun begins a clause, it usually refers to the subject of the previous clause. In this case, 'tourists' is the subject of the preceding clause. This only worsens the problem in this option, since 'their' seems to be pointing to 'tourists'.

I hope this helps to clarify your doubt!

Regards,
Meghna
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Hi there,

Usually, when a pronoun begins a clause, it refers to the subject of the previous clause. In this context, the subject of the previous clause is "tourists". So, even though the logical antecedent of the pronoun "they" can't be "tourists", it's better to replace the pronoun with the noun that it should refer to.

As we point out in our SC1 live session, pronoun ambiguity is sometimes considered an error on the GMAT, but sometimes an ambiguous pronoun can be in the correct answer. So, we encourage you not to use pronoun ambiguity as the only criterion to eliminate an answer choice.

In this question, there is also another way to eliminate option A. Note the difference between "visit... and see" and "visit... to see". The intended meaning of the sentence is that tourists visit the zoo in order to see the rhinos. This meaning is correctly stated by using "to" rather than "and". The part before the semicolon also makes it clear that the sentence is concerned only with rhinos, and that any other reason that tourists may visit the zoo is not part of the intended meaning of the sentence. So, "visit... to see" is correct.

I hope this helps to resolve your doubt.

Regards,
Meghna
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As per OG The verb following after should
be the present-perfect have been trimmed to reflect
that the trimming must occur before the tourists
arrive.

But already the time maker after is there, so why is it necessary to use present perfect tense here

Also what is the basic difference in using whether and if? When to use if and when to use whether?

Hi Ashish,

Time markers such as "before" and "after" should be used to substitute actions only when the past perfect tense is used. This rule does not apply to the present perfect tense, since this tense doesn't need two actions. The present perfect tense refers to an action that started in the past and has continued into the present. It can stand on its own without reference to any other action.

"If" should be used in "if-then" contexts: i.e., the conditional use. E.g. 'If X happens, Y will happen'. 'Whether' is used when there is a choice between two things. E.g. It is unclear whether the company will increase production. Meaning: the company may increase production, or it may not.

I hope this helps!

Regards,
Meghna
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I'm trying to understand significance and correctness of use of "one" in phrase "to see one after the animals' horns have been trimmed" in choice E. Sure the choice E don't sound as precise as option C. But what does "one" imply? It seems choice E says that tourists will continue to visit parks to see a rhinoceros (one of the many rhinoceroses) once the animals horns are trimmed. The phrase is generally used in spoken english. Is it correct?

Dear @dipsy001,

Thank you for posting this question. I believe you can arrive at the answer on your own. Just pay close attention to the original sentence.

A proposal has been made to trim the horns from rhinoceroses to discourage poachers; the question is whether tourists will continue to visit game parks and see rhinoceroses after their horns are trimmed.

Is the original sentence saying that the tourists will see 1 rhino or many rhinos in general?

Now look at your understanding of choice E (which by the way is correct!!). Do you think the two match?

Thus without getting into the grammatical nuances, you can eliminate choice E on the account of meaning shift from the original sentence

Hope this helps.

Regards,
Payal
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Is this grammatically correct ?

See those two girls. Helen is the one on the left.
here one should refer to girl.
but girl is not mentioned anywhere in the sentence.But girls is mentioned.

ravi's car broke down,so he walked back to the hotel.

here he has no referent.As ravi's car is mentioned but ravi is not mentioned.

please help.