Correct Answer: B

Rationale: Choice B is the correct answer because it serves as a transition sentence in the paragraph about the Silk Road. It shifts the focus from Chinese silk being a major trade item to the introduction of other important trade items that had a significant impact on the world. This transition indicates a change in the topic being discussed within the paragraph. Choices A, C, and D do not serve as transition sentences. Choice A simply introduces the origin of the Silk Road's name, choice C provides additional information about the network without transitioning to a new topic, and choice D gives a general description of the Silk Road without transitioning to a different aspect of the trade routes.

Correct Answer: B

Rationale: The correct answer is B: "Termites are very industrious insects." This is a simple sentence as it contains a subject (termites) and a verb (are) and expresses a complete thought. Choice A is not a simple sentence as it is a dependent clause starting with 'Although' and does not express a complete thought. Choice C is a compound sentence since it consists of two independent clauses joined by the conjunction 'and.' Choice D is a complex sentence with a dependent clause starting with 'Because' and an independent clause.

Correct Answer: D

Rationale: In this sentence, 'increasingly' is functioning as an adverb. Adverbs modify verbs, adjectives, or other adverbs to describe the manner, degree, or frequency of an action. In this case, 'increasingly' describes how the difficulty of the hike was growing as we approached the mountain top. Choice A, 'Adjective,' is incorrect as adjectives modify nouns or pronouns, not verbs. Choice B, 'Interjection,' is also incorrect because interjections are words used to express strong emotions or sentiments, not to describe actions or qualities. Choice C, 'Verb,' is incorrect as 'increasingly' is not a verb; it does not express an action or state of being.

Correct Answer: A

Rationale: The subject 'Neither' is singular, so the correct verb form to use is 'is.' In this sentence, 'boys' is part of a prepositional phrase 'of the boys' and does not affect the verb agreement. 'Are' (choice B) is plural and does not match the singular subject. 'Were' (choice C) is past tense and not suitable for the present context. 'Be' (choice D) is an infinitive form and does not agree with the subject.

Correct Answer: B

Rationale: The correct answer is B: 'is, are'. 'Where is everyone?' requires the singular verb 'is' to agree with 'everyone'. 'What are they doing?' requires the plural verb 'are' to match the plural subject 'they'. Option A 'is, is', does not provide correct subject-verb agreement in the second sentence. Option C 'are, is' and Option D 'are, are' do not maintain consistent subject-verb agreement within the sentences.