The verb in the underlined portion of the sentence is in the present tense, while the verb in the first part of the sentence is in the past tense. The two verbs need to match their tenses due to the construction of the sentence. The correct answer choice is " none proved satisfactory."

The sentence describes what the soldier had already done to his own body. The use of "himself" is correct and necessary to show who the action was done to, but the action occurred in the past, meaning the appropriate verb form is "backed." The correct answer choice is "had backed himself."

The use of the verb "learn" is essentially as a modifier of the students "shock." This means that "learning" must be turned into a form that will describe why the students were "shocked." "Were shocked to learn," using an infinitive form, is the best choice among the answers.

The example sentence features a verb tense error. Since "described" is in the past tense and the writing Boswell did about Johnson contains descriptions of Johnson, the verb "writing" should agree with the tense of "described." Replacing the underlined section with "and wrote that" is the correct answer.

While "asserts" and "says" are both potentially correct verbs to insert, those options were in the present tense, and thus would be incorrect in this context.

The phrase "and has written" would need to be a separate clause, and would require a comma preceding it to be correct.

We know that the proper tense to describe an event that happened "over the course of past year" is the present perfect, which narrows down potentially correct answer choices to either "have increased the company's profitability" or "has increased the company's profitability."

Since the subject of the increasing event is "wave," not "advances," we should go with the answer choice that uses the singular verb—"has increased the company's profitability."

This sentence contains an error in verb voice. The phrase "Japanese longswords...are considered..." is in the passive voice. Since there is already an interrupting appositive renaming the subject here, it is best to simply re-phrase this sentence in the active voice in order to avoid an overly wordy and complex sentence. The most clear and concise choice in this instance is, "Many individuals consider Japanese longswords, katanas, the best swords in the world." The other choices are too wordy or contain inconsistencies (e.g. longswords...a katana).

This sentence is structured as an independent clause about a priority and then a clarification of what that priority is.

The only appropriate punctuation here is a colon, which will provide that correct structural division and allow the second part of the sentence ("studying physics before her final exam the next morning") to act as an explanation of the noun "priority."

INCORRECT EXPLANATIONS:

A semicolon connects two separate independent clauses, so that is incorrect.

Janine's priority is "studying," which is a gerund, so the past tense "studied" is incorrect.

The option that uses a comma is incorrect because the second clause is dependent and is lacking a subject.

The option that uses a colon unnecessarily includes the connector "and that was." These superfluous words cloud the sentence's meaning and make the sentence grammatically incorrect.

The use of the verb "seeming" in the sentence makes the sentence incomplete. As "seeming" is a gerund, or a verb form that functions as a noun, there is actually no verb in the sentence. The correct answer is "seemed to get worse over time."

The use of the verb "learn" is essentially as a modifier of the students "shock." This means that "learning" must be turned into a form that will describe why the students were "shocked." "Were shocked to learn," using an infinitive form, is the best choice among the answers.

The example sentence features a verb tense error. Since "described" is in the past tense and the writing Boswell did about Johnson contains descriptions of Johnson, the verb "writing" should agree with the tense of "described." Replacing the underlined section with "and wrote that" is the correct answer.

While "asserts" and "says" are both potentially correct verbs to insert, those options were in the present tense, and thus would be incorrect in this context.

The phrase "and has written" would need to be a separate clause, and would require a comma preceding it to be correct.