— Was the driving pleasant when you went to Mexico last summer?
— No, it ＿＿ for four days when we arrived, so the roads were very muddy.
A. was raining
B. had been raining
C. would be raining
D. rained
网友回答
A. was raining
(答案→)B. had been raining
C. would be raining
D. rained
解析：表示在过去某一动作之前一直在进行，并有可能继续下去的动作，要用过去完成进行时。