介绍:
主动被动的转换
被动结构不一定是被)也可以是由，为，所，等等
例句：
Nothing can be seen in the dark room. (被动变主动)
He appeared in the room and was warmly welcomed by the audience (受到).
There are known to be thousands of dfferent languages. (加主语)
It is reported that Taiwan authorities refused to accept any help from the mainland. (特殊结构)
主动被动的转换
结构补充
It is hoped that
It is said that
It has been announced that
It is assumed that
It is considered that
It is noticed that
大家还在听
