The infinitive verb “to sharpen” should not be split in half by the adverb “quietly,” or any other word. The adverb must be moved elsewhere so the infinitive is not split. The “-ly” ending on the adverb is necessary because without it, “quiet” remains an adjective and is grammatically incorrect.

The problem with the original sentence is that the phrase “even though she was mortally afraid of sharks” interrupts the flow of the main clause. The sentence runs more smoothly when it is placed at the beginning. It is important to preserve the coordinator “even though” in this sentence, because it is key to the logic of the statement. This answer choices that change this are incorrect.

The underlined phrase has a problem with the phrase "most learning." The phrase is describing the word "scholars." While the scholars might have "the most learning," this would make them "the most learned." The correct answer is "even the most learned of scholars."

The insertion of "that" between "studies" and "have" makes the sentence unclear and strangely incomplete, as the sentence essentially becomes a dependent clause. By placing "that" after "shown," the sentence becomes much more clear and appropriately makes the dependent clause after the main body of the sentence. The correct answer choice is "Studies have shown that pets can help people with problems such as depression and anxiety."

The insertion of "only" at the beginning of the sentence creates confusion as to exactly what it is modifying. The word should be moved to make it clear it is modifying "time," which is the way the sentence makes the most sense. Therefore, the correct answer choice is "The only time that will work."

The placement of "exactly" in the sentence is confusing, as placing it after "like" makes it seem as though the manner was almost exactly or kind of exactly. By placing "exactly" after "was," the comparison between the two manners of speech is more clear, making the correct answer "His manner of speech was exactly like his grandfather's."

The word "merely" is dangling in the middle of the sentence, seemingly modifying nothing and making little sense in the sentence. The word should be moved to indicate a clearer usage of the adverb. The place where the word makes most sense is between "information" and "confused," so it is clear that it is modifying the verb "confused."

The placement of "barely" in the sentence is extremely odd, as it seems to imply that the subject only lightly pushed, but still got the stone "five yards." The word "barely" needs to be moved to clarify that the stone "barely" made the distance. Thus, "He pushed the stone barely five yards," is the correct answer choice.

The use of "Only" at the beginning of the sentence is strange and confusing, making it unclear what it is modifying. The construction of the rest of the sentence means the word should modify "issue" directly. "The only issue that mattered" is the answer choice that correctly deploys the adjective.

The placement of "barely" in the sentence as confusing, as it modifies "dug" and makes the sentence read that the team was not digging very much. The meaning of the sentence is more clear if "barely" modifies the "two feet" to show how little was actually done. The answer choice that correctly deploys "barely" is "the team had dug barely two feet into the hard ground."