語態(tài)有兩種：主動語態(tài)和被動語態(tài)。
主語是動作的發(fā)出者為主動語態(tài)；主語是動作的接受者為被動語態(tài)。
1)若賓語補足語是不帶to的不定式，變?yōu)楸粍诱Z態(tài)時，該不定式前要加“to”。此類動詞為感官動詞。
feel，hear，help，listento，lookat，mak英語e，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)動詞+be+過去分詞，構成被動語態(tài)。
Coal can be used to produce electricity for agriculture and industry。
本文來自：逍遙右腦記憶 http://www.yy-art.cn/gaozhong/1133742.html
相關閱讀：�？荚~的語法與用法：entrance, equal, equip