Correct Answer: C

Rationale: The correct answer is 'C: Had known.' In this sentence, the structure is a third conditional, which is used for unreal situations in the past. 'Had known' is the correct past perfect form that matches the conditional structure. It indicates that if they had possessed the knowledge about the bad weather in advance, they wouldn't have gone to the beach. Options A, B, and D do not correctly fit the past perfect tense required in this context. 'Know' (Option A) is present tense, 'Knew' (Option B) is simple past tense, and 'Were knowing' (Option D) is incorrect and does not convey the intended meaning of the sentence in the context of a third conditional.

Correct Answer: B

Rationale: In this sentence, the correct form is the gerund 'going' after the preposition 'to.' The gerund form is used after prepositions to indicate an action or state. Therefore, 'Going' is the correct choice to complete the sentence. Choice A ('Go') is incorrect because it is not the gerund form required after 'to.' Choice C ('Be going') is incorrect as it is not the standard form used in this context. Choice D ('Going to go') is redundant and unnecessarily wordy.

Correct Answer: A

Rationale: In this sentence, 'Oneself' is the correct reflexive pronoun to use when referring back to the singular subject 'a person.' It is important to match the reflexive pronoun with the singular noun. 'Yourself' and 'Themselves' are plural forms and do not agree with the singular subject 'a person.' 'Itself' is used for inanimate objects, not for people. Therefore, 'Oneself' is the most suitable choice in this context.

Correct Answer: B

Rationale: In this sentence, 'Economics' is a singular subject, so it should be paired with a singular verb. 'Is' is the correct verb to use with a singular subject like 'Economics.' Therefore, the correct sentence is: 'Economics is my least favorite subject at school.' Choice A 'Am' is incorrect because it is a first-person singular form of the verb 'to be' and does not agree with the subject 'Economics.' Choice C 'Are' is incorrect as it is a plural verb form and does not match the singular subject 'Economics.' Choice D 'Been' is incorrect as it is a past participle and cannot be used as the main verb in this sentence structure.

Correct Answer: A

Rationale: The correct answer is A: 'As soon as the puppies were asleep' is the dependent clause in the sentence. It functions as an adverbial clause, indicating a time relationship with the action of the mother dog leaving her bed. Dependent clauses rely on independent clauses to form complete sentences and cannot stand alone. Choice B is incorrect because it separates the dependent clause. Choice C is incorrect as it is a noun phrase. Choice D is incorrect as it is an independent clause.