GMAT Sentence Correction: Punctuation

GMAT Sentence Correction will test your comprehension of the sentence’s meaning as well as its grammar, style, and concision, by giving you more answer choices that are grammatically correct (but still wrong). In this series of articles, I want to explore the ways this can happen, with some example questions for you as well. First, let’s talk about punctuation.
Sentence A: Let’s eat, Grandma!
Sentence B: Let’s eat Grandma!
Sentence C: Every dog knows its master.
Sentence D: Every dog knows it’s master.
The ancient Romans wrote with little or no punctuation, and usually without even putting any spaces between the words. It is hard to imagine the confusion that could arise from that, when in English a simple mark (such as a comma or an apostrophe) can make such difference in the sense of the sentence. In the first pair, Sentence A conveys familial devotion, while B implies cannibalism; in the second pair, Sentence C features man’s best friend looking up to humans, while in Sentence D, the dog looks down on humans.
Of course, the GMAT is unlikely to feature something so simple (or potentially comical), but punctuation is often needed to reduce ambiguity or to change the meaning of a phrase or clause. Here are a few quick tips to remember:

Relative Clauses

Clauses starting with a relative pronoun like which, who, or that are prime candidates for a change in meaning, especially ones starting with which or that.

Semicolons and Commas

Because they separate clauses, semicolons and commas can also change the meaning of a sentence by changing the point where one clause begins and another ends.

Punctuation Practice Question

On her way to the store, Priya decided to purchase a personal organizer, a new computer with a wireless network card, and a barking toy robot dog that would make her life easier, she decided.
A. and a barking toy robot dog that would make her life easier, she decided.
B. and a barking toy robot dog; that would make her life easier, she decided.
C. and a barking toy robot dog that would make her life easier; she decided.
D. and a barking toy robot dog making her life easier, she decided.
E. and, deciding that would make her life easier, a barking toy robot dog.

Answer and Explanations

A. Incorrect. While grammatically correct, the placement of that suggests that the barking toy would make her life easier, when it makes more sense for it to be either the whole purchase or just the non-toy portions.
B. Correct. By putting that into a new independent clause, it can make a stronger claim to modify the preceding clause. You can still argue that that refers back to the toy, but the connection is not as strong as it is in the other sentences.
C.  Incorrect. Though this one is technically grammatically correct, that modifies the toy again, and “she decided” is a very uninformative independent clause.
D.  Incorrect. Placing the present participle making directly next to the toy dog suggests it is the barking toy making her life easier, which isn’t likely (has anyone’s life ever been made easier by a barking toy dog?).
E. Incorrect. The placement of and before the deciding suggests they are part of the same unit: the final item in her list of purchases. This also suggests the toy will make her life easier.
I don’t believe you’ll see a question exactly like this on the GMAT; that’s not the point. The idea here is to show how the placement of punctuation can affect how you interpret certain parts of sentences.