He had already finished studying at a(n) _____ when he was called to join the army.

Correct Answer: A

Rationale: In the context provided, the correct answer is 'university.' The term 'university' is used to refer to higher education institutions that offer undergraduate and postgraduate degrees. While 'academy,' 'college,' and 'institute' are also types of educational institutions, 'university' is the most fitting choice here as it best aligns with the idea of completing higher education before joining the army.

Correct Answer: B

Rationale: The correct answer is 'B - was.' In the original question, 'were' is incorrectly used as the verb, which should be singular to match the singular subject 'procedure.' The subject 'procedure' requires the singular form 'was' instead of the plural form 'were.' Choices A, C, and D are all used correctly in the sentence.

Correct Answer: A

Rationale: The correct answer is A because the phrase 'walking to school' seems to modify 'a dollar,' which is illogical. The intended meaning is that the child found the dollar while walking to school. In sentence B, the modifier is correctly placed at the beginning of the sentence, indicating that the child found the dollar while walking to school. Choices C and D do not contain any misplaced modifiers.

Correct Answer: B

Rationale: The correct answer is 'She was going to the store.' This sentence uses the correct form of the past continuous tense, which is appropriate for describing an action in progress in the past. Choice A is the only option that uses the correct verb form. Choice C uses the present perfect tense, which is not suitable for describing a past action in progress. Choice D is incorrect as it lacks the auxiliary verb 'has' in the sentence structure.

Correct Answer: B

Rationale: The correct sentence structure is 'The cat is sleeping on the mat.' This is a complete and grammatically correct sentence following a standard subject-verb-object structure. 'The cat' is the subject, 'is sleeping' is the verb, and 'on the mat' is the prepositional phrase describing where the action is taking place. Choices A, C, and D are incorrect. Option A is a sentence fragment lacking a verb; option C is a dependent clause lacking a main clause, and option D has a subject-verb inversion making it awkward and incorrect.