不定式是指帶to的動詞原形(使用中有時不帶to),在句中起形容詞或副詞的作用, 可以作狀語和定語。

　　(一)作定語

　　1. 動詞不定式與其修的詞之間往往有動賓關(guān)系, 如果該不定式是不及物動詞, 其后有必要的介詞。

　　He’s pleasant fellow to work with.

　　There’s nothing to worry about.

　　2. 有些名詞后常跟不定式作定語。例如: time, reason, chance, right, ability, willingness, need, anxiety, wish, plan等。

　　Women should have the right to receive education.

　　There is no time to hesitate.

　　3. the first, the second, the last, the best 等之后用不定式做定語。

　　The monitor will be the first to come.

　　He was the last man to blame.

　　(二)作狀語

　　1. 作目的狀語

　　不定式作狀語時, 其動作發(fā)生在謂語動詞之后, 一般置于句子末尾。但是, 如果表示強調(diào), 亦可置于句首。其否定形式為: 在不定式符號前加not。

　　He went to Shanghai to visit his parents.

　　To save the earth, we must prevent the earth from being polluted.

　　I shut the door quietly, so as not to wake the baby.

　　2. 作結(jié)果狀語

　　We came home after our holiday to find our garden neat and tidy.

　　She left home, never to return again.

　　3. 作原因狀語

　　不定式做原因狀語時, 一般放在句子末尾。

　　She burst into laughter to see his funny action.

　　The boy was shocked to see the frightening scene.

　　4. 作獨立成分

　　有些固定詞組帶to不定式, 表明說話人的立場或態(tài)度, 在句中作獨立成分。

　　這些詞有:

　　to be honest, to begin with, to cut a long story short,to get (back) to the point, not to make much of it,to put it another way, to tell the truth等。

　　To tell you the truth, I have never been to Beijing.

　　To be honest, I have never heard of Winston Churchill.

　　We can’t go. To begin with, it’s too cold.我們不能去。首先,天太冷了。

　　To cut a long story short, I decided to stay.簡而言之,我決定留下。

　　In the cousre of a day students do far more than just attend classes.(more than+不帶to的不定式)