Correct Answer: C

Rationale: 'Carried' is correct because 'should never be' requires the past participle form of the verb 'carry' to complete the sentence properly. The sentence is in the passive voice, indicating that the action is being done to the scissors, not by them. Choices A, B, and D are incorrect as they do not form the correct past participle form needed in this context.

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: C

Rationale: 'Carried' is correct because 'should never be' requires the past participle form of the verb 'carry' to complete the sentence properly. The sentence is in the passive voice, indicating that the action is being done to the scissors, not by them. Choices A, B, and D are incorrect as they do not form the correct past participle form needed in this context.

Correct Answer: A

Rationale: The correct answer is 'Was studying,' which is the past continuous form describing an action that was happening at a specific time in the past. Choice B, 'Didn't study,' is incorrect because it's in simple past tense, not the continuous form required by the context. Choice C, 'Studied hard,' is incorrect as it lacks the continuous aspect required by the context. Choice D, 'Would have studied,' is in the wrong tense; it is a hypothetical past action, not an action in progress in the past.

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.