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"Rate of addition" and "rate of loss" are both singular, so verbs that associate with them should be plural. That's why this one is tricky. Thanks, sujay, for the link to the other discussion!

Danielle wrote:"Rate of addition" and "rate of loss" are both singular, so verbs that associate with them should be plural. That's why this one is tricky. Thanks, sujay, for the link to the other discussion!

The correct answer uses the singular verb, "rises". The only reason that the first half of the sentence uses "drop" instead of "drops" is because it's in the future (i.e. the whole verb is "will drop"). Since the connector used is "while", the second verb should be in the present tense. If the connector had been "and", the second part of the sentence would have used the verb "will rise" (or just "rise", since we don't need to repeat "will" if it applies to both verbs).

"Rate of addition" isn't underlined, so we need to make the other part of the sentence parallel to it.

Therefore, we want to pick a choice that eliminates "those" (which is plural) and says either "that of loss" or "the rate of loss", which leads us to (D).

I believe that the answer is D.
THe rate of X will drop while rate of Y rises.
Its the closest one that holds a good comparison!

Thanks Stuart

for clarifying the doubt of, why we have not used "drops"
Good Explanation
In b/w, i have doubt.....
when we use "while".....is it that the tense following while should be in present and the tense which precedes "while" should be in future tense....

Stuart Kovinsky wrote: The correct answer uses the singular verb, "rises". The only reason that the first half of the sentence uses "drop" instead of "drops" is because it's in the future (i.e. the whole verb is "will drop"). Since the connector used is "while", the second verb should be in the present tense. If the connector had been "and", the second part of the sentence would have used the verb "will rise" (or just "rise", since we don't need to repeat "will" if it applies to both verbs).

"Rate of addition" isn't underlined, so we need to make the other part of the sentence parallel to it.

Therefore, we want to pick a choice that eliminates "those" (which is plural) and says either "that of loss" or "the rate of loss", which leads us to (D).

panacea6565 wrote:Thanks Stuart

when we use "while".....is it that the tense following while should be in present and the tense which precedes "while" should be in future tense....

Let's look at a few more examples:

I will do my homework while my sister watches tv.

The choir will sing songs as the bus drives us to the concert.

The waiter will be jealous while the customers eat dinner.

In each case, the first verb is in the future tense and the second in the present.

For some reason this same pattern doesn't hold true if we're talking about the past. It would be correct to say:

I did my homework while my sister watched tv.

The choir sang songs as the bus drove us to the concert.

The waiter was jealous while the customers ate dinner.

Gotta love English!

D:correct
dont fully agree , but best among the rest.

maintains Parallelism :- the rate will drop and the rate rises & correct SV use :-Rate is singular so rises.

But I have one doubt. while is to represent 2 events happening simultaneously.

Here one is in future and one is in present..

pls explain.

Stuart Kovinsky wrote: The correct answer uses the singular verb, "rises". The only reason that the first half of the sentence uses "drop" instead of "drops" is because it's in the future (i.e. the whole verb is "will drop"). Since the connector used is "while", the second verb should be in the present tense. If the connector had been "and", the second part of the sentence would have used the verb "will rise" (or just "rise", since we don't need to repeat "will" if it applies to both verbs).

"Rate of addition" isn't underlined, so we need to make the other part of the sentence parallel to it.

Therefore, we want to pick a choice that eliminates "those" (which is plural) and says either "that of loss" or "the rate of loss", which leads us to (D).

Hi Stuart,

Thanks for your awesome reply...can you please tell what is wrong with E ?

Thanks
Mohit