Since the road is wet this morning, last night．A.it must rainB.it must be rainin
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Since the road is wet this morning, ________ last night．
A.it must rain
B.it must be raining
C.it must have rained
D.it must have been rain
试题答案
C
解析：must have done用于对过去发生的事情进行推测，且较有把握。