高中学历解放军武警士兵考军校-英语知识汇总（六十七）

 　　二、The Passive被动语态

　　下列情况下使用被动语态：

　　不知道动作的执行者时。

　　要关注的事动作的本身而不是动作执行者时。

　　要特别关注动作执行这时，

　　要避免句子主语太长时。

　　被动语态主要用于正式的表达和书面语中，是非常典型的报刊和报道用语，除了动词时态的被动形式外，还有其他被动形式：

　　不定式的被动语态： It's nice to be taken seriously.

　　动名词的被动形式：We all enjoyed being praised by the teacher.

　　不定式的被动完成形式：The train may have been delayed by the storm.

　　三、Emphatic structures： inversion and "it" cleft sentences.

　　强调结构，倒装句和分裂句"it"

　　把否定词（如seldom）置于句首形式倒装表示强调，即用疑问句的语序。这样的强调句通常用于正式的书面语中。

　　He was never known anything like it. Never has he known anything like it.

　　倒装形式的强调也可以用于对过去事实进行假设的条件中。

　　注意形成倒装时，要将if去掉。这样的倒装句常见于正式和非正式的表达中。

　　If I had known they were in town， I would have phoned them.

　　= Had I known they were in town， I would have phoned them.

　　在正式和非正式的表达中，可以用下列结构对某些词语进行强调。

　　It's money that he's interested.

　　四、表达完成的动词形式

　　表达完成的动词形式可以用来表达某特定时间前发生的动作。

　　I've been staying with my family on the coast.

　　在下列情况下用表达完成的动词形式：

　　现在完成时

　　现在完成进行时

　　过去完成时

　　过去完成进行时

　　将来完成时：We will have moved out by the end of next year.

　　不定式完成式：They may have lost their way.

　　动词ing形式的完成式： I remembered having met the man long time ago.