Two hours have elapsed since he had fallen asleep. A. fell B. has fallen C. was fallen D. No improvement

The correct answer is D. No improvement.

The sentence “Two hours have elapsed since he had fallen asleep”

is in the past perfect tense. The past perfect tense is used to talk about an action that happened before another action in the past. In this case, the action that happened before is “two hours have elapsed.” The action that happened after is “he had fallen asleep.”

The past perfect tense is formed with the past participle of the verb and the auxiliary verb “had.” The past participle of “fall” is “fallen.” So, the correct sentence is “Two hours have elapsed since he had fallen asleep.”

The other options are incorrect because they do not use the past perfect tense. Option A, “fell,” is in the simple past tense. Option B, “has fallen,” is in the present perfect tense. Option C, “was fallen,” is in the past passive voice.

The past passive voice is not used in this sentence because the sentence is not about something that happened to someone or something. The sentence is about something that someone did.