Whereas the use of synthetic fertilizers has greatly

[RonPurewal]

Hello,

Is the usage 'their substitution for more traditional fertilizers ' in A correct?

it's never worthwhile to ask this question about an official problem.
OFFICIAL ANSWERS TO OFFICIAL PROBLEMS ARE ALWAYS CORRECT.
this means that everything in those answers choices is correct, even if it appears to be ugly.

Can you help me understand with some other example in the form of a sentence.

from this sentence, we can deduce that you can use "X's substitution for Y" to refer to a situation in which Y is removed and replaced by X.

another example:
soybean oil is becoming more and more prevalent in the american diet; its substitution for more expensive oils, such as olive oil, is ubiquitous in budget restaurants.

i'm not the biggest fan of this construction either, but remember that it's useless to question official answers -- all we can do is learn from them.

[alvin8139]

look at just this part of choice d:

... while if substituted for more traditional fertilizers, this substitution

you can't do this.
if you precede a clause with an initial modifier that doesn't have a subject, then the noun IMMEDIATELY FOLLOWING THE COMMA is automatically assigned as the subject of that modifier.
so:
in this choice, you're saying, weirdly enough, that 'this substitution' is 'substituted' for more traditional fertilizers.
that doesn't make sense, as i'm sure you'll agree.

Excellent explanation, Ron! I have some further questions. Is the structure "while if" correct? It seems bit strange to me. I understand 'while' is normally used in GMAT for introduce contrast. Is it correct? While + clause...(introduce contract); While doing...(meaning at the same time doing...). "While if..." seems to be neither of the above-mentioned structure. pls help me understand that better. Thanks.

[gayathri248]

Choice A, I thought had a pronoun error with 'their'? Can it not refer to parts of the world?

[RonPurewal]

Excellent explanation, Ron! I have some further questions. Is the structure "while if" correct? It seems bit strange to me. I understand 'while' is normally used in GMAT for introduce contrast. Is it correct? While + clause...(introduce contract); While doing...(meaning at the same time doing...). "While if..." seems to be neither of the above-mentioned structure. pls help me understand that better. Thanks.

i admit that those two words look strange next to each other. (note that they appear in an incorrect answer in this problem, so you cannot glean any useful information about their usage from here.)

still, it's possible to construct a correct sentence with "while" and "if" next to each other. in such a sentence, your analysis here wouldn't be proper -- you wouldn't consider "while if" to be a single unit. instead, the construction would be structured so that "while" served as a conjunction preceding the whole clause, but "if" began the clause itself.
for instance:
if placed out in the sun, this chemical may explode, while if placed in the freezer, it may freeze and thereby expand, causing its container to burst.
this is not the world's most beautiful sentence, and i suspect that this usage would not be written into an officially correct answer, but sometimes gmac surprises us with its usage.

[vicksikand]

Whereas the use of synthetic fertilizers has greatly expanded agricultural productivity in many parts of the world, an increase in their use can create serious environmental problems such as water pollution, and their substitution for more traditional fertilizers may accelerate soil structure deterioration and soil erosion.

,and their substitution ....:their can easily refer to either serious environmental problems or synthetic fertilizers.

[vicksikand]

what is the OA?

gmat_s - the guy who posted this problem says its D, the other members are more inclined towards A. If this is a GMAT Prep problem, then there should be no confusion.

[tim]

Vicks, the first "their" has a clear antecedent, so the GMAT is intending the second "their" to refer to the same thing. As Ron said, our job is to understand why the correct answer is correct, not to argue against it. The correct answer is A..

[akshat.itmec]

hey experts,
i was just wondering if there was an easier way to eliminate option D::
I came across this rule
IF present then can/may
so with the IF part in past can we rule out the option solely based on this ?
pls ans..

[danielpatinkin]

"...the increased usage of these fertilizers can create serious environmental problems such as water pollution, while if substituted for more traditional fertilizers, this substitution may accelerate soil structure deterioration and soil erosion."

In the structure above, the word "substituted" is NOT a verb. It is a past participle functioning as an adjective describing "synthetic fertilizers."

Therefore, you cannot use if/then tense sequence as an eliminating principle in D.

Another way to eliminate D is to recognize that the phrase "if substituted for more traditional fertilizers" is a noun modifier that should refer to, and therefore touch, "synthetic fertilizers." However, the noun that follows the noun modifier is "this substitution." Therefore we have an incorrect modifier.

Happy Holidays!
- Dan P

[saintjingjing]

en, I say this sc from prep
and I want to know whether IN A an increase in their use is more better than in D the increased usage of these fertilizers or not?
from parallel, whereas the use of synthetic fertilizers....
D, the increased usage of these fertilizers is more better than IN A an increase in their use ?

[saptadeepc]

look at just this part of choice d:

... while if substituted for more traditional fertilizers, this substitution

you can't do this.
if you precede a clause with an initial modifier that doesn't have a subject, then the noun IMMEDIATELY FOLLOWING THE COMMA is automatically assigned as the subject of that modifier.
so:
in this choice, you're saying, weirdly enough, that 'this substitution' is 'substituted' for more traditional fertilizers.
that doesn't make sense, as i'm sure you'll agree.

also could you please explain if we can compare use to usage/ use to increase ????

i'm not quite sure what you're asking here.

Ron, a qq on this.

I was confused between a phrase and a clause so I googled them.

A phrase does not have a SUBJECT doing the VERB.

and

A clause is a collection of words that has a subject that is actively doing a verb

You said this is a clause without SUBJECT.

My question is, can there be a clause without a SUBJECT ? Also, substituted is a participle and not a VERB, so what exactly does this piece of sentence act as ?

On the same lines, will the SUBJECT always come just after the comma whenever we see such modifiers ?

[RonPurewal]

Ron, a qq on this.

I was confused between a phrase and a clause so I googled them.

A phrase does not have a SUBJECT doing the VERB.

and

A clause is a collection of words that has a subject that is actively doing a verb

You said this is a clause without SUBJECT.

well, "this substitution" is the start of a clause. i didn't see a need to copy the entire clause.

My question is, can there be a clause without a SUBJECT ?

i don't think so, but i can't absolutely guarantee that (grammatical terms are not my strong point.)

Also, substituted is a participle and not a VERB, so what exactly does this piece of sentence act as ?

it's an initial modifier that must talk about the following subject (which should be directly after the comma).
if you're looking for a grammatical term, i'm sorry, but i have no idea what it's called.

On the same lines, will the SUBJECT always come just after the comma whenever we see such modifiers ?

if the modifier is used correctly, yes.

[thanghnvn]

Stacey, members, pls, explain fully why C is wrong?

[jnelson0612]

Stacey, members, pls, explain fully why C is wrong?

C says "if these fertilizers are used increasingly" which is incorrect wording. Correct wording would be something such as "if these fertilizers are increasingly used".

[thanghnvn]

I do not understand the following, pls, help explain clearly.

C says "if these fertilizers are used increasingly" which is incorrect wording. Correct wording would be something such as "if these fertilizers are increasingly used".

Moreove,
Dose C contain any other errors? I am not easy with C but do not understand why.

I can eliminate B,E,D but can not eliminate C though I see that C is not good. But I do not understand why. pls, help.