具体来说就是, 主动态动词如要变成被动态, 是把助动词be变为主动态动词原来的时态, 更加上主要动词的过去分词.
主动态动词的主语这时变为被动态动词的施动者.
这个施动者常常不被提到.
若要提到, 可置于by之后或放在从句的后面.
如:
This tree was planted by my grandfather.
这棵树是我祖父种的.
主动态:
We keep the butter here.
我们把黄油放在这儿.
被动态:
The butter is kept here.
黄油在这里放着.
主动态:
They broke the window.
他们把玻璃窗打碎了.
被动态:
The window was broken by them.
玻璃窗被他们打碎了.
主动态:
They won’t hold the meeting tomorrow.
他们明天不会举行会议.
被动态:
The meeting won’t be held tomorrow.
明天不再举行会议.
主动态:
People have seen wolves in the streets.
人们在街上见到过狼.
被动态:
wolves have been seen in the streets.
在街上看到过狼.