主語(yǔ)和賓語(yǔ)換個(gè)位置 動(dòng)詞前面加be動(dòng)詞 動(dòng)詞變成被動(dòng)形式（通常后面加ed）
如果主語(yǔ)是動(dòng)作的承受者,或者是說動(dòng)作不是由主語(yǔ)而是由其他人完成的,則用被動(dòng)語(yǔ)態(tài).主動(dòng)語(yǔ)態(tài)→被動(dòng)語(yǔ)態(tài)：
1、找到該句賓語(yǔ)（必須是在謂語(yǔ)動(dòng)詞后的）,將它提到句子開頭.
2、用被動(dòng)語(yǔ)態(tài)結(jié)構(gòu)be+Vt過去分詞構(gòu)成句子.
3、把原句的主語(yǔ)用by構(gòu)成的介詞短語(yǔ)帶出,也可不加.
eg：I finished my homework yesterday.
→My homework was finished (by me) yesterday.
特殊形式：
1、部分Vi加上適當(dāng)介詞可當(dāng)作Vt構(gòu)成被動(dòng)語(yǔ)態(tài).
eg：Parents look after their children carefully.
→Children were looked after (by parents) carefully.
2、聯(lián)系動(dòng)詞沒有被動(dòng)語(yǔ)態(tài).eg：The water feels warm.
3、在主動(dòng)語(yǔ)態(tài)中一些省略to的動(dòng)詞不定式改為被動(dòng)語(yǔ)態(tài)時(shí)需加上to.
eg：Teachers often make him stand outside.
→He is often made to stand outside (by teachers).
4、have、let等動(dòng)詞無被動(dòng)語(yǔ)態(tài).
必要時(shí),have可改為held,let sb to do sth可改為be allowed to do sth (被允許做某事）.