Check out this subtle Comparison question! As usual, try it on your own first, then check out the explanation below! Bonus if you can do it in under 1.5 min!

Providing initial evidence that airports are a larger source of pollution than they were once believed to be, environmentalists in Chicago reported that the total amount of pollutant emitted annually by vehicles at O’Hare International Airport is twice as much as that which is being emitted annually by all motor vehicles in the Chicago metropolitan area.

A) as much as that which is being emitted annually by all
B) as much annually as is emited by the
C) as much compared to what is annually emitted by all
D) that emitted annually by all
E) that emitted annually compared to the

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Let’s look at the formation of the sentence:

Modifying clause, NOUN VERB “the total amount…emitted annually…” PREPOSITIONAL PHRASE…“is twice as much as that which is being emitted annually PREPOSITIONAL PHRASE.”

We need the two boldest segments to be parallel and concise, and to show the correct comparison.

“the total amount” is a noun, so “that” correctly replaces it. Therefore we can eliminate answer choices (B) and (C). (A) has the unnecessary word “being,” so that leaves (D) and (E).

If we plug in (E), the sentence reads “emitted annually compared to the motor vehicles in the Chicago metropolitan area.” It’s awkward to “compare” the amount of pollutant with the motor vehicles. We need a correct preposition to describe that the cars are doing the emitting.

On a personal note, I think of the word “being” as a big red flag. It usually means that a sentence is written in passive voice, and that there is a more active verb available. In fact, I cannot remember EVER seeing a correct answer choice with the word “being” in it.

The answer is (D). It makes the clearest comparison.

“the total amount of pollutant emitted annually BY….
…is twice that emitted annually BY all…”

NOUN…VERB…ADVERB…PREPOSITION