語態(tài)有兩種：主動(dòng)語態(tài)和被動(dòng)語態(tài)。

　　主語是動(dòng)作的發(fā)出者為主動(dòng)語態(tài)；主語是動(dòng)作的接受者為被動(dòng)語態(tài)。
　1）若賓語補(bǔ)足語是不帶to 的不定式，變?yōu)楸粍?dòng)語態(tài)　時(shí)，該不定式前要加"to"。此類動(dòng)詞為感官動(dòng)詞。
feel, hear, help, listen to, look at, make, observe, see, notice, watch

　　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）情態(tài)動(dòng)詞+ be +過去分詞，構(gòu)成被動(dòng)語態(tài)。
　　 coal can be used to produce electricity for agriculture and industry.

let 的用法
　1）當(dāng)let后只有一個(gè)單音節(jié)動(dòng)詞，變被動(dòng)語態(tài)時(shí)，可用不帶to 的不定式。
　　 they let the strange go.---> the strange was let go.
　
　2） 若let 后賓補(bǔ)較長時(shí)，let 通常不用被動(dòng)語態(tài)，而用allow或permit 代替。
　　the nurse let me go to see my classmate in the hospital.
　　----> i was allowed / permitted to see my classmate in the hospital.

短語動(dòng)詞的被動(dòng)語態(tài)
　短語動(dòng)詞是一個(gè)整體，不可丟掉后面的介詞或副詞。
　　this is a photo of the power station that has been set up in my hometown.
　　my sister will be taken care of by grandma.　　
　　such a thing has never been heard of before..

表示"據(jù)說"或"相信" 的詞組
　　believe, consider, declare, expect, feel , report, say, see, suppose, think, understand

it is said that…　　 據(jù)說　　
it is reported that… 據(jù)報(bào)道　　　
it is believed that…　大家相信　　　　　
it is hoped that…　大家希望
it is well known that… 眾所周知　　
it is thought that…　大家認(rèn)為
it is suggested that…　據(jù)建議　　　　　
it is taken granted that…　 被視為當(dāng)然　
it has been decided that… 大家決定　　
it must be remember that…務(wù)必記住的是

it is said that she will leave for wuhan on tuesday.