Question

帮忙解释let；see；watch；fell；make后面的动词用原型，但在被动语态中用to do，什么时候要用？怎么用？

什么是被动语态？怎么用？多举几个例子

Answer 1

被动语态就是 被....着
主语+过去分词 过去分词就是动词+ed 当然也有特殊的，需要特别记忆。
例子：主动 ;The children gave the foreign guests a warm welcome
被动：The foreign guests were given a warm welcome by the children
孩子们热烈欢迎外国游客
外国游客被孩子们热烈欢迎

Answer 2

被动语态：be 动词+done(过去分词）
eg. I beat you. 我打你
You are beated by me.你被我打
1. let him sleep
he is let to sleep
2. i see him sleep
he is seem to sleep
3. i watch him dance
he is watched to dance

Answer 3

因为这些词为使役动词，平时学的这些词后跟动词原型，其实是省略了to，因此，在被动语态中，才需要加上to~

Answer 4

其实平时只是省略了let、see等的不定式（to…）在被动语态中不定式（to…）要还原，所以被动语态中要用to do。懂了吧 (*^__^*)