If it had been fine yesterday we could have watched that air show. But it all day. A. ha

问题补充：

If it had been fine yesterday, we could have watched that air show. But it all day.

A. has rained

B. had rained

C. rained

D. rains

答案：

A. has rained

B. had rained

(答案→)C. rained

D. rains

解析： 考查时态。根据yesterday，应用一般过去时，所以选C。