語態有兩種：主動語態和被動語態

　　主語是動作的發出者為主動語態；主語是動作的接受者為被動語態。

　　1）若賓語補足語是不帶to 的不定式，變為被動語態　時，該不定式前要加"to"。此類動詞為感官動詞。

　　feel, hear, help, listen to, look at, 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）情態動詞+ be +過去分詞，構成被動語態。

　　Coal can be used to produce electricity for agriculture and industry.