问题补充:
It last night., because the ground is all wet
A. should rain
B. should have rained
C. must rain
D. must have rained
答案:
A. should rain
B. should have rained
C. must rain
(答案→)D. must have rained
解析:考察情态动词的推测性用法。根据last night可知,本句是对过去动作的推测,即排除AC, B意为本应当下雨(而实际上没有下雨),D,意为一定下雨了。
句意为昨天晚上肯定下雨了,因为地上都湿了。