they must have lost your letter in the post.They must have lost your letter in the post改被动语态your letter must have been lost by them in the post 1、有MUST的是什么时态.2、MUST后不是直接跟动词原型吗.
问题描述：
they must have lost your letter in the post.
They must have lost your letter in the post
改被动语态
your letter must have been lost by them in the post
1、有MUST的是什么时态.
2、MUST后不是直接跟动词原型吗.
答
你好:
1 有 must 的可以是 一般现在时态, 也可以是一般过去时态 , 也可以是完成时态 .
如: You must be on time (一般现在时态)
You must drunk too much (一般过去时态)
You must have lost your letter in the post (现在完成时态)
2 must 是情态动词, 后面接动词原形, 所以上面的主动句和被动句中 , 都用的是 have ,是动词
原形, 而不是其他形式
希望对您有帮助!
答
must have done sth.对过去情况的推测,本身有可能是过去时,也有可能是完成时.意为：肯定
如：
He has been to Beijing .-----He must have been to Beijing.(完成时）
It rained last night----It must have rained last night (过去时）
have 也是动词原形.