被动语态的基本用法

1.强调动作的承受者

The time-table has been changed.时间表已变动了。（强调“时间表”）

These books are written especially for children.

这些书是专门为孩子们写的。（强调“这些书”）

2.不知道谁是动作的执行者

His bike has been stolen.他的自行车被人偷走了。（不知道自行车是谁偷的）

The front window in the classroom was broken yesterday.

昨天，教室的前窗被打破了。（不知谁打破的）

3.动作的执行者者不重要，不明显

George was wounded in the war.乔治是在战争中受伤的。（谁让乔治负伤不重要）

They have been poorly paid.他们的工资太低。（没必要指出工资是谁付的）

4.出于修辞的原因，或是说为了更好地安排句子时

The proposal is especially opposed to by those who have invested much in the area.这个提议特别遭到了那些在本地区投资很大的人的反对。（those的定语太长，为了避免句子松散）

5.表示客观的说明常用“It’s+过去分词”句式。

It’s said that Lucy has gone abroad.据说露西已经出国了。

It’s reported that an accident happened this morning.据报道今天上午发生了一起事故。

It’s believed that printing was first invented by the Chinese.

人们相信印刷术最早是由中国人发明的。