Question

The playground is wet this morning.It must rain last night.isn't it？为什么

Answer 1

It must rain last night.isn't it？这整个句子都是错的.用isn't it来反问,更是错的.

(The playground is wet this morning)早上操场还是湿的，由此推测昨晚肯定下雨了.

对过去情况肯定的推测,应用must have done sth. , 其反意问句是用didn't 来反问.

因此It must rain last night.isn't it？应改为:

It must have rained last night, didn't it？
昨晚肯定下雨了, 对吗?

Answer 2

什么为什么。

追问

为什么用isn't it 变反意疑问句

追答

这是固定用法，翻译过来“不是吗？
”
因为是翻译疑问，所以要用反过来来提问，懂了没？？