高三英語知識點：動詞不定式的用法

1、高三英語知識點：動詞不定式的用法3. 不定式作主語1) Its easy (for me) to do that. 我做這事太容易了。easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;the first, the next, the last, the best, too much, too little, not enoughIts so nice to hear your voice.聽到你的聲音真高興。Its necessary for you to lock th

2、e car when you do not use it. 當(dāng)你不用車的時候，鎖車是有必要的。2) Its very kind of you to help us. 他幫助我們，他真好。kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考慮周到的), silly, selfish(自私的)It was silly of us to believe him.我們真愚蠢，竟然相信了他。It seemed selfish of him not to give them anyt

3、hing.他不給他們?nèi)魏螙|西，這顯得太自私了。注意1) 其他系動詞如，look，appear等也可用于此句型2) 不定式作為句子成分時，動詞用單數(shù)形式。3) 當(dāng)不定式作主語的句子中又有一個不定式作表語時，不能用It is to的句型(對)To see is to believe.百聞不如一見。(錯)It is to believe to see.Its for sb.和 Its of sb.1) for sb. 常用于表示事物的特征特點，表示客觀形式的形容詞，如easy, hard, difficult, interesting, impossible等：Its very hard for h

4、im to study two languages. 對他來說學(xué)兩門外語是很難的。2) of sb的句型一般用表示人物的性格，品德，表示主觀感情或態(tài)度的形容詞，如good, kind, nice, clever, foolish, right。Its very nice of you to help me. 你來幫助我，你真是太好了。for 與of 的辨別方法用介詞后面的代詞作主語，用介詞前邊的形容詞作表語，造個句子。如果道理上通順用of，不通則用for。如：You are nice.(通順，所以應(yīng)用of)。He is hard.(人是困難的，不通，因此應(yīng)用for。)4. 不定式作表語不定式可

5、放在be動詞后面，形成表語。例如：My work is to clean the room every day.His dream is to be a doctor.5. 不定式作定語不定式做定語通常要放在被修飾的詞后。例如：I have a lot of work to do.So he made some candles to give light.6. 不定式作狀語1) 目的狀語To only to (僅僅為了), in order to, so as to, so(such) as to (如此以便)He ran so fast as to catch the first bus.他

6、飛快地跑以便趕上第一班車。I come here only to say good-bye to you.我來僅僅是向你告別。2) 作結(jié)果狀語，表事先沒有預(yù)料到的，要放在句子后面。What have I said to make you angry.He searched the room only to find nothing.3) 表原因Im glad to see you.典型例題The chair looks rather hard, but in fact it is very comfortable to _.A. sit B. sit on C. be seat D. be s

7、at on答案：B.如果不定式為不及物動詞，其后應(yīng)有必要的介詞。當(dāng)動詞與介詞連用時，常位于形容詞+動詞不定式結(jié)構(gòu)的末尾。用作介詞的toto 有兩種用法：一為不定式+動詞原形; 一為介詞+名詞/動名詞, to 在下面的用法中是第二種，即to+ 名詞/動名詞：admit to承認(rèn)，confess to承認(rèn)，be accustomed to 習(xí)慣于，be used to 習(xí)慣于，stick to 堅持，turn to開始，著手于，devote oneself to 獻(xiàn)身于，be devoted to 致力于， look forward to 盼望，pay attention to注意省to 的動詞不定式1) 情態(tài)動詞 ( 除ought 外，ought to)：2) 使役