If you’ve already spent a reasonable amount of time studying for SAT Writing, there’s a pretty good chance you’ve seen parallelism questions that look like this:

Incorrect: Susan likes running, playing soccer, and to hike.

Correct: Susan likes running, playing soccer, and hiking.

In case you’re unfamiliar with the rule, it’s that all of the items in a list (typically three) must be in the same format: either verb, verb, verb; noun, noun, noun; or gerund, gerund, gerund. No mixing and matching!

But “lists” involving three items aren’t the only of parallelism that gets tested on the SAT. In fact, there’s another kind that only deals with two items.

Two-part parallelism, while based on the same principle, is a little bit trickier. Instead of dealing with words, it deals with entire phrases. Furthermore, because most prep books don’t even cover it, many people get caught off guard when they encounter it on the actual test.

In addition, this structure often tested in conjunction with word pairs. Spot the word pair, and you can answer the question quickly.

Here’s the rule:

The construction of a phrase on one side of a given conjunction must match the construction of the phrase on the other side of that conjunction as closely as possible.

I realize that’s very abstract, so let me give you an example:

Incorrect: The researchers called for enforcement of tobacco regulations as well as investigating motivations for smoking.

The first thing we can notice about this sentence is that it contains a conjunction, “as well as,” and that there is a phrase on either side of it. So what were the two things researchers called for?

1) Enforcement of tobacco regulations (noun + of + adjective + noun)

2) Investigating motivations for smoking (gerund + noun + preposition + noun)

Clearly, the two sides do not match. The SAT will virtually always ask you to correct the second side, and so we need to rewrite the second side in accordance with the structure “noun + of + noun,” which is the absolute classic structure that the SAT loves to use.

Correct: The researchers called for the enforcement of tobacco regulations as well as an investigation of motivations for smoking.

If it helps, think of it as the English equivalent of balancing an equation.

Now here’s why it’s really important that you be able to both recognize and correct this type of error with little to no effort: it usually shows up at the end of Fixing Sentences — typically as either the last or the second-to-last question of the section (#10 or 11 on the first section; #13 or 14 on the second), so there’s a very good chance you’ll see it after sitting through four-and-a-half hours or more of testing. You won’t have the energy to think about it. The good news is that if you can recognize what the question is testing, you can usually jump right to the answer choice.

For example, let’s consider the following real question (October ’06 test, section 10, #14):

Acquaintances of Alexei have commented that he is at once annoying because of his unpredictability but his imagination is still a delight.

(A) but his imagination is still a delight
(B) although he is delightfully imaginative
(C) and he is delightful in his imagination too
(D) while being imaginative and they are delighted
(E) and delightful because of his imagination

If you can recognize the word pair “at once…and,” that immediately gets you down to (C) and (E).

But how to decide between them? The structure before the conjunction is “adjective + because of + noun” (annoying because of his unpredictability) you know that the other side must contain that same construction as well.

If you just look for the words “because of,” that leads you right to (E), which is indeed the answer.