注：☆被动语态的时态是由be的时态决定的，be是什么时态，全句就是什么时态，be后面的过去分词不变。

　　㈡用法：

　　例：①History is made by the people. (一般现在时)

　　②The cars were made in Tianjing in 1995. (一般过去时)

　　③The tree will be cut down next year.(一般将来时)

　　④The room must be kept clean.　（含有情态动词的被动语态）

　　⑤The door is being opened.　（现在进行时）

　　⑥The film has been seen by me.　（现在完成时）　

　　三、被动语态的各种句型：

　　1. The song is liked by young people. (肯定句)

　　2. The song isn't liked by young people.（否定句）

　　3. Is the song liked by young people ?（一般疑问句）

　　4. Who is the song liked by?=By whom is the song liked?（特殊疑问句）

　　四、主动语态改被动语态的方法：

　　方法分为三步：⑴把原句中的宾语改成主语

　　⑵动词改为变动形式be done(同时注意时态)

　　⑶原来的主语如果需要的话放在介词by后面，以指明做的人或物，如果没有必要则省去

　　例：The man killed a tiger.

　　→ A tiger was killed by the man .(改的过程中要注意时态和语态两个方面)

　　五、特殊句型的被动语态：

　　⑴含有使役动词（make /let /have）或感官动词（hear ,see, listen to ,look at ,find ,watch, feel等）的句子，在主动语态中这些词后常跟不带to的动词不定式，但是在改成被动语态时，则一定要把省去的to再加上去，另外help这一个词在主动语态中后面的动词不定式可以带to,也可不带to, 但在被动语态中也必须把to加上去。

例：①Mother often makes me do some housework.

→I am often made to do some housework by mother.

②We saw him run into the classroom.

→He was seen to run into the classroom by us.