Question

(2013·高考新课标全国卷Ⅱ)Since nobody gave him any help，he________have done the research on his

(2013·高考新课标全国卷Ⅱ)Since nobody gave him any help，he________have done the research on his own. A．can　　　　　　　 B．must C．would D．need

Answer 1

B

选B。分析主从句逻辑关系，主句是对从句表达的原因的一种猜测，must have done想必/准是/一定做过某事，符合主从句之间的逻辑关系。本题句意为“既然没人给他帮忙，那他肯定是自己做的研究”。can have done 用于疑问句或否定句中，表示对过去情况的推测；would have done表示过去将来完成时或用于虚拟语气中；need have done 通常用于否定句和疑问句中，表示“本不必做某事却做了”。