Correct Answer: C

Rationale: The word 'understand' should be used instead of 'understands' to maintain subject-verb agreement. In this sentence, 'few' is a plural subject, requiring the plural verb 'understand' rather than 'understands.' The corrected sentence reads, 'but few truly understand the essay.' Choice A, 'pretends,' is used correctly in the sentence. Choice B, 'truly,' is also used appropriately. Choice D, 'essay,' is also correctly used in the sentence.

Correct Answer: B

Rationale: The correct word to use in this sentence is 'has' because 'One of the students' is singular, so it should be followed by a singular verb. The word 'has' is the correct singular form of the verb in this context. Choice A 'have' is plural, Choice C 'are' is also plural, and Choice D 'is' does not agree in number with the subject 'students'. Therefore, 'has' is the only correct choice here.

Correct Answer: A

Rationale: The correct word to use in this sentence is 'volunteered' as it indicates an action that Cathy did in the past. The sentence suggests that Cathy was engaging in volunteering at the hospital for the first time, so the past tense form 'volunteered' is the most appropriate choice. Choice B ('volunteering') is incorrect because it is the present participle form and does not fit the past tense context of the sentence. Choice C ('was volunteered') is passive voice and implies that someone else made Cathy volunteer, which is not the intended meaning. Choice D ('volunteer') is incorrect as it is the base form of the verb and does not match the past tense requirement of the sentence.

Correct Answer: B

Rationale: The sentence needs a comma before the conjunction 'but' to correctly join the two independent clauses 'The days seem long' and 'the nights seem even longer.' This comma helps to create a clear separation between the contrasting ideas in the sentence. Choice A (Period) is incorrect because a period would create two separate sentences rather than connecting them. Choice C (Colon) is incorrect as colons are used to introduce lists, explanations, or quotations. Choice D (Apostrophe) is incorrect as it is not needed in this sentence.

Correct Answer: B

Rationale: In the sentence 'One out of four doctors,' the subject is 'One,' which is singular. Therefore, the verb that follows should also be singular. The correct verb form in this case is 'subscribes,' not 'subscribe' or any other form. This subject-verb agreement rule ensures that the sentence is grammatically correct. Choice A 'subscribe' is incorrect as it is in the plural form and does not agree with the singular subject. Choice C 'subscribing' is in the gerund form and does not function as the main verb of the sentence. Choice D 'are subscribed' is in the passive voice and does not match the active voice required in this sentence.