It's for sb.和 It's of sb.
1)for sb. 常用于表示事物的特征特点,表示客观形式的形容词,如easy, hard, difficult, interesting, impossible等:It's very hard for him to study two languages. 对他来说学两门外语是很难的。
2)of sb的句型一般用表示人物的性格,品德,表示主观感情或态度的形容词,如good, kind, nice, clever, foolish, right。It's very nice of you to help me. 你来帮助我,你真是太好了。
3)for 与of 的辨别方法:用介词后面的代词作主语,用介词前边的形容词作表语,造个句子。如果道理上通顺用of,不通则用for。如:You are nice. (通顺,所以应用of)。
He is hard. (人是困难的,不通,因此应用for。)
不定式作状语
1)目的状语:To… only to (仅仅为了), in order to, so as to, so(such)… as to… (如此……以便……)
He ran so fast as to catch the first bus. 他飞快地跑以便赶上第一班车。
I come here only to say good-bye to you. 我来仅仅是向你告别。
2)作结果状语,表事先没有预料到的,要放在句子后面。
He searched the room only to find nothing.
3) 表原因 I'm glad to see you.
典型例题
The chair looks rather hard, but in fact it is very comfortable to ___.
A. sit B. sit on C. be seat D. be sat on
答案:B. 如果不定式为不及物动词,其后应有必要的介词。当动词与介词连用时,常位于"形容词+动词不定式"结构的末尾。
不定式的时态和语态
时态\语态 主动 被动
一般式 to do to be done
进行式 to be doing
完成式 to have done to have been done
完成进行式 to have been doing
1) 现在时:一般现在时表示的动词,有时与谓语动词表示的动作同时发生,有时发生在谓语动词的动作之后。 He seems to know this.
I hope to see you again. = I hope that I'll see you again. 我希望再见到你。
2) 完成时:表示的动作发生在谓语动词表示的动作之前。
I'm sorry to have given you so much trouble.
He seems to have caught a cold.
3) 进行时: 表示动作正在进行,与谓语动词表示的动作同时发生。
He seems to be eating something.
4) 完成进行时:
She is known to have been wreaking on the problem for many years.
省to 的动词不定式
1) 情态动词 ( 除ought 外,ought to):
2) 使役动词 let, have, make:
3) 感官动词 see, watch, look at, notice , observe, hear, listen to, smell, feel, find 等后作宾补,省略to。
注意:在被动语态中则to 不能省掉。
I saw him dance. =He was seen to dance.
The boss made them work the whole night. =They were made to work the whole night.
4) would rather,had better:
5) Why… / why not…:
6) help 可带to,也可不带to, help sb (to) do sth:
7) but和except:but前是动词do时,后面出现的动词用不带to的动词不定式。
8) 由and, or和than连接的两个不定式,第二个to 可以省去:
9) 通常在discover, imagine, suppose, think, understand等词后,可以省去to be:
He is supposed (to be) nice. 他应该是个好人。
举例: He wants to move to France and marry the girl.
He wants to do nothing but go out.
比较: He wants to do nothing but go out.
He wants to believe anything but to take the medicine.
典型例题 1) ---- I usually go there by train.
---- Why not ___ by boat for a change?
A. to try going B. trying to go C. to try and go D. try going
答案:D. why not 后面接不带to 的不定式,因此选D。
2) Paul doesn't have to be made ___. He always works hard.
A. learn B. to learn C. learned D. learning
答案:B. make后接不带to 的动词不定式,当其用于被动时,to 不可省略。
动名词与不定式
1) 动名词与不定式的区别:
动名词表达的是: 状态,性质,心境,抽象,经常性,已发生的
不定式表达的是: 目的,结果,原因,具体,一次性,将发生的
2) 接不定式或动名词,意义相同。
3) 动名词与不定式语义不同的有11 组:
1 stop to do stop doing
2 forget to do forget doing
3 remember to do remember doing
4 regret to do regret doing
5 cease to do cease doing
6 try to do try doing
7 go on to do go on doing
8 afraid to do afraid doing
9 interested to do interested doing
10 mean to do mean doing
11 begin/ start to do begin/ start doing