to do 不定式的用法

當to do作主語：一般用it作形式主語，不定式后置，具體的句型為It's adj/noun(for sb)to do。當to do作賓語：1.謂語動詞＋動詞不定式（多數動詞屬于此類動詞）；2.系表結構+動詞不定式。

當to do不定式作賓語補足語

1、具體結構為：主語＋謂語＋賓語＋動詞不定式

例如：The teacher urged his students to prepare for the exam.

老師勸他的學生準備考試。

Their help enabled me to finish the work with ease.

他們幫助我，使我能夠順利地完成工作。

2、當動詞不定式做make, have, let, hear, see, feel等動詞賓語的補足語，要省略“to”

例如：My father will probably have Tom paint the house green.

我爸爸很可能叫湯姆把房子漆成綠色。

I felt my heart beat violently.

我感覺到自己的心跳得很厲害。

當to do不定式作目的狀語

1、具體結構為：in order/so as + 動詞不定式

例如：He must work very hard in order to support his large family.

他必須拼命工作以養活他的大家庭。

Listen carefully so as to follow the teacher.

要仔細聽才能聽懂老師講的課。

2、具體結構為：be used + 動詞不定式

例如：The book is used as a reference book.

這本書被用來做參考書。