一.不定式

　　1.定義：具有名詞、形容詞及副詞性質(zhì)并具有時態(tài)、語態(tài)變化。

　　2.形式：(以do為例)

　　主動語態(tài) 被動語態(tài)

　　一般時 to do to be done

　　進(jìn)行時 to be doing

　　完成時 to have done to have been done

　　完成進(jìn)行時 to have been doing

　　3.用法：

　　(1)用作主語：

　　To speak good English is not easy.

　　or: It is not easy to speak good English.

　　(采用形式主語 it 以避免頭重腳輕)

　　It took me an hour to do the work.

　　(2)用作賓語：

　　She decided to take the examination.

　　I hope to meet him soon.

　　(3)賓語補(bǔ)足語：

　　They expected us to help them.

　　Hewants his son to study hard.

　　重點：

　　不定式作賓補(bǔ)，如謂語動詞是感官動詞，使役性動詞(see, hear, notice, watch, make, have, let...)，則不定式符號“to”須省略，但在被動語態(tài)中不能省。

　　I heard them sing in the classroom.

　　I made her clean the room.

　　The girl is heard to sing an English song.