问题补充：
We had a bad weekend. It all the time.
A. rains
B. has rained
C. is raining
D. was raining
答案：
A. rains
B. has rained
C. is raining
(答案→)D. was raining
解析：句意:我们度过了一个很糟糕的周末。一直在下雨。rain 下雨，是一个动词。根据句意和句中的We had a bad weekend可知，这里说的是一件过去的事情，故应该用过去时，故选D，过去进行时。A是一般现在时；B是现在完成时；C是现在进行时，都不符合句意。
