In any "neither . . . nor" phrase, each item being compared has to be the same kind of item so a proper comparison can be made. The sentence is written with two different elements, the simple noun "antibiotics" and the verbal phrase "the use of disinfectants." The only answer choice that uses an appropriate parallel structure, by redeploying the verbal phrase to cover both items, is "Neither the use of antibiotics nor disinfectants helped slow."

The initial sentence is correct. The use of "either" in this manner requires that it be accompanied by "or."

"Chatting online" is a gerund phrase, while "video games" is a noun. In an "either . . . or" phrase, however, both elements of the phrase need to be of the same kind of word. "Either chatting online or playing video games might appear" is the only answer choice that uses an appropriate parallel structure.

Parallelism is the key here—all the descriptions should be in the same format, which is a single word adjective. The correct answer also makes the sentence more concise and more fluid, which is another benefit of having parallel sentence structure and another way to tell which answer choice is best.

As it is written, the sentence uses parallelism incorrectly because the two things the governor supports are different word forms - "abolishing residential taxes" is a gerund phrase, and "to create new state parks" is an infinitive phrase. Changing the infinitive phrase to a gerund phrase makes the sentence sound more fluid.

The sentence must have parallel structure. The quantifier “some” should appear before each fruit, or it should be left out completely. The verb “to decide” must be followed by an infinitive verb (“to buy”).

The sentence suffers from a form of faulty parallelism, in which the third item in a parallel series doesn't share the same grammatical form as the other items in the series. The third item, "he desired to win," is stated as a clause, while the other two items, "agility" and "grace," are nouns. The easiest way to fix this problem is simply to change "he desired" to "a desire."

The list that makes up the underlined portion of the sentence does not correctly employ parallel structure, making it actually describe wildly different things, like the act of "managing" with the topic of "computer science." The three elements in the list need to have the same structure, making "computer science, leadership techniques, and account management," the correct answer choice, as here, all of the elements are presented as nouns.

Elements in a list must have the same grammatical structure in order to be parallel. In this case, the first two items in the list are gerunds: "practicing" and "eating." The third item in the list, however, is a noun: "classes." To correct the sentence's error, the noun "classes" should be replaced by a gerund, and the only answer choice that does this without introducing other errors is "practicing French, eating regional food, and taking classes during their trip abroad."

This sentence's error is one of parallel structure: all of the items in the sentence's list need to be written in the same form. As it is written, the sentence's list includes one present progressive verb ("taking") and two past-tense verbs ("unfolded" and "curled up"). All of these items need to match, so we either need to change "unfolded" and "curled up" to "unfolding" and "curling up," or "taking" to "took." "He was seen took" is grammatically incorrect; we need the present progressive verb, "taking." So, we need to change "unfolded" and "curled up" to "unfolding" and "curling up," making the correct answer "What do you make of the fact that he was seen taking off his shoes, unfolding a blanket, and curling up for a nap in one of the café's booths?"