Question

It _____ last night., because the ground is all wet A．should rain B．should have rained .

It _____ last night., because the ground is all wet A．should rain B．should have rained C．must rain D．must have rained

Answer 1

D

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。