This sentence uses “that” where “which” is more appropriate. Use “which” for added information, after a comma. The corrected sentence reads, "The last question, which was asked by the town’s famously off-kilter librarian, addressed the completely irrelevant issue of protection against government spying."

This sentence uses the wrong version of there/their. The possessive “their” is appropriate in this case. The corrected sentence reads, "Judging from their aversion to loud noises, I doubt that the cats will enjoy having three toddlers running amok."

“That” would be a better substitute for “which” since the island we’re referring to is a thing. “Which” is used to refer to an action and/or introduce a new clause, especially after a comma. For example, “I couldn’t understand the directions, which bothered me.”

This sentence contains a common usage error—the word "accepted," meaning allowed into, has been confused with the word "excepted," meaning specifically left out. Confusing these words completely changes the meaning of the sentence.

In this sentence, the phrase "had been involved in the hit-and-run from last year" is not a subordinate clause. Rather, it is part of the main clause and helps to identify which truck in particular the speaker is referring to. Because it is not subordinate, the use of the word "which" is inappropriate and confusing. The word "that" should be used instead.

This sentence mixes up the words “that” and “which.” “Which” is used to start a phrase that provides additional information after a comma. The content of a which-phrase is loosely connected to the content of the main phrase, and the sentence would still make sense if the information contained in the phrase were omitted. “That” directly follows the word it’s modifying, with no comma intervening. The corrected sentence reads, "Nancy brought over the most heavenly-smelling batch of pecan rolls, which would have been lovely if I weren’t allergic to both nuts and gluten."

"It's" is the contraction, meaning "it is." "Its," without the apostrophe, is the possessive pronoun - the correct one that should be used here. This is a VERY common error, just remember that this is a rare case where the possessive form specifically does not take an apostrophe.

Although "you're" is correct the first time it appears in the sentence, it is a contraction of "you are;" it is, in other words, a subject and a verb. In the second half of the sentence, "happy days" is an object that the speaker is talking about, and "you're" should be changed to your, the possessive form of the pronoun "you." This makes it clear that she has happy days, but is not herself made of happy days. To see the problem more clearly, replace "you're" with "you are" every time it appears: "...I hope to multiply you are happy days..."

The sentence's introductory clause seems to intend to describe the subject "he," but it begins with a verb that doesn't clearly connect to the rest of the sentence and is grammatically incorrect. Introductory clauses can begin with participles, which would make much more sense in this sentence by allowing the start of the sentence to connect clearly to the subject. Of the potential answer choices, only "Having been immersed" omits the incorrect verb and replaces it with a grammatically correct participle. The other answer choices don't make sense: "Immersion having happened" and "Immersion happening" don't clearly connect the first phrase to the subject, and "He who had been immersed" introduces a grammatical error by making the sentence contain two disconnected subjects, "He who had been immersed in the literature since childhood" and "he." The corrected sentence reads, "Having been immersed in the literature since childhood, he maintained an appreciation for it as an adult."

The issue in the underlined portion of the sentence is the use of the verb form "existing," which is a participle and not an actual verb. The word needs to be changed into a form that functions as a verb. "Conflicting desires exist in every single person" is the correct choice among the answers.