Correct Answer: D

Rationale: The sentence 'However, online students often work entirely from home, which is just one part of what makes online learning different.' provides a contrast and smoothly transitions to a discussion of what makes online learning distinct from traditional classroom settings. Choice A talks about the components of a course but does not transition to a new point. Choice B discusses similarities between online and traditional courses, which does not transition to a new topic. Choice C focuses on interactions with professors but does not transition to a new idea.

Correct Answer: C

Rationale: The correct answer is 'C: Quickly.' Adverbs modify verbs, adjectives, or other adverbs. In this sentence, 'quickly' describes how she finished her homework. Choice A 'She' is a pronoun, choice B 'Finished' is the verb, and choice D 'Homework' is a noun, making them incorrect choices for adverbs.

Correct Answer: A

Rationale: The correct answer is 'A: is.' In the sentence, 'Our family is staying home for the holidays this year,' the singular collective noun 'family' requires a singular verb to maintain subject-verb agreement. 'Is' is the correct singular form of the verb to match with 'family.' Choice B 'be' is incorrect as it is the base form of the verb and does not agree with the subject 'family.' Choice C 'am' is incorrect as it is a first-person singular form of the verb 'to be,' which does not align with the subject 'family.' Choice D 'are' is incorrect as it is a plural form of the verb and does not match with the singular subject 'family.'

Correct Answer: D

Rationale: The correct answer is D, 'chocolate cookies and vanilla cupcakes.' In this sentence, the friendly baker is the subject, 'offered' is the verb, and 'chocolate cookies and vanilla cupcakes' receive the action of the verb, making them the direct object. Choices A, B, and C do not directly receive the action of the verb 'offered,' so they are not the direct object. Choice A is the verb phrase, choice B is a prepositional phrase, and choice C is the subject of the sentence.

Correct Answer: C

Rationale: The comma after 'home' is unnecessary and should be removed. In this sentence, 'and' is joining two independent clauses, which doesn't require a comma before it. Choices A, B, and D are incorrect because they are correctly placed commas within the sentence.