单项选择题
Since the road is wet,（） last night.
A.it must have rained B.it must rain C.it must be raining D.it must have been raining
单项选择题 （）that it was raining, he put on his raincoat.
单项选择题 When did you see her? What （） then?
单项选择题 When Jack arrived, he learned Mary （） for almost an hour.
