1.定義：具有名詞、形容詞及副詞性質并具有時態、語態變化。

    2.形式：（以do為例）

    主動語態被動語態一般時 to do to be done 進行時 to be doing完成時 to
have done to have been done 完成進行時 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 ）賓語補足語：They expected us to help them. Hewants his son to
study hard. 金牌重點：不定式作賓補，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.

    （4 ）用作表語：To teach is to learn. His job is to sell cars.

    （5 ）用作狀語，表示目的，結果：We come to school to study English.
（目的）

    = in order to I hurried to the store， only to find it closed.（結
果）

    （6 ）定語：不定式短語作定語須位于名詞之后。

    He asked for a piece of paper to write it on. = to write it on the
piece of paper. The poor man has no house to live in. = to live in the
house. Have you anything to do？

    = to do anything

    4.不定式的時態意義：She seems to dance very well. （現在情況）

    She seems to be dancing in the dancing hall.（正在進行）

    She seems to have danced well.（過去情況）

    Has was happy to have been staying with his uncle.（動作持續一段時
間）

    5.不定式語態：The doctor [wrecommend]recommended[/w] him to air the
room. The doctor recommended the room to be aired. She expects the police
to find her bicycle. She expects her bicycle to be found by the police.
She felt a bit puzzled as he had asked her such a question. She felt a
bit puzzled to have been asked such a question.

    6.不定式否定形式：not to do ……

    He got up early in order not to miss the train.

    測試精編

    1. Did you find out ________ the pie out of oven？

    A. to take B. have taken C. when to take D. being taken

    2. You would be irritated if you watched the mail ________ on your
desk every day. A. putting up B. to be put up C. to pile up D. pile up

    3. We shall set Jim ________ the passage. A. explaining B. explained
C. to explain D. explain

    4. In fact， she would rather leave for San Francisco ________ in
Los Angeles. A. tostay B. than stay C. than staying D. than have stayed

    5. Madame Curies is believed ________ the radium. A. discovering B.
having discovered C. to have discovered D. to discover

    （后設答案，大家不要偷看哦~ （*^__^*）嘻嘻……）

    KEYS

    1. C 2. D 3. C 4. B 5. C