Question

The ground is wet all over, so I’m sure it must have rained last night, ________?

A. wasn’t it
B. didn’t it
C. isn’t it
D. doesn’t it

Answer 1

答案B
本题考查反义疑问句。I’m sure it must have rained last night, ________?
主句主语为I，所以对从句反问，it must have rained last night，有具体的过去时间last night，所以用一般过去式didn’t it 。如果没有具体的过去时间，则用完成时hasn’t it。所以选B。