大学英语：语态：

语态有两种：主动语态和被动语态。不及物动词或动词短语无被动语态：
　　主语是动作的发出者为主动语态；

主语是动作的接受者为被动语态。结构：be+动词过去分词
1）若宾语补足语是不带to 的不定式，主动语态句子变为被动语态时，该不定式前要加"to"。此类动词为感官动词。
    feel, hear, help, listen to, look at, make, observe, see, notice, watch
例句：
　　The teacher made me go out of the classroom.
     --> I was made to go out of the classroom (by the teacher).
　　 We saw him play football on the playground.
     --> He was seen to play football on the playground.
2）情态动词+ be +过去分词，构成被动语态。
　　 Coal can be used to produce electricity for agriculture and industry.

3）常用的被动语态句型：

在形式主语句中，用believe, consider, declare, expect, feel , report, say, see, suppose, think, understand等词的被动语态带主语从句表示转述或泛指。
It is said that…　　 据说　　
It is reported that… 据报道　　　
It is believed that…　大家相信　　　　　
It is hoped that…　大家希望
It is well known that… 众所周知　　
It is thought that…　大家认为
It is suggested that…　据建议　　　　　
It is taken granted that…　 被视为当然　
It has been decided that… 大家决定　　
It must be remember that…务必记住的是
例句：It is said that she will leave for Wuhan on Tuesday.