上海新东方酷学酷玩夏令营：

动词的语态
　　　　 语态有两种：主动语态和被动语态。

　　　　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。

　　　 1）若宾语补足语是不带to 的不定式，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

　　　　 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.