2022年中考英语动词不定式用法教案

动词不定式用法教案
动词不定式没有人称和数的变化，在句中不能独立作谓语。但动词不定式具有名词、形容词和副词特征，在句中可以作主语、宾语、宾语补足语、定语、表语和状语等多种成分。另外，动词不定式具有动词特点，可以有自己的宾语和状语，组成动词不定式短语。动词不定式的肯定形式是to＋do；其否定形式是not to＋do。
下面以动词不定式在句中的作用来予以详细说明。
1．作主语
(1) 直接作主语
To see is to believe．百闻不如一见。
To finish the work in ten minutes is very hard.
To learn English well is not easy.
(2) 但在英语中，常用it作形式主语，真正的主语即动词不定式放在后面。如：
It is very hard to finish the work in ten minutes.
It is not easy to learn English well.
It's wrong to play tricks on other people．
It's our duty to keep our environment clean and tidy．
规律：动词不定式在句中作主语时，常放在以下两个句型中，it仅作形式主语，不定式是真正的主语。
It is ＋adj．（形容词）＋ to do sth．和It is ＋n．（名词）＋ to do sth．句型中
下面我们来具体看一下这两个句型的用法：
① 常用形容词作it is的表语。真正主语不定式通常有逻辑主语，一般用for/of短语来表示，即for/of sb．to do sth．（其中sb．就是to do的逻辑主语）
It's important for us to keep the water clean．保持水质清洁对我们来说是很重要的。
辨析：It is + adj. + for sb. + to do和 It is + adj. + of sb. + to do ，区别如下：
A. It's 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。
B. It's 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。
【说明】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。 或者: To study two languages is hard for him。 因此应用for。)
② 有时也接名词作表语。如：
It must be great fun to fly to the moon in a spaceship．乘宇宙飞船飞往月球一定很有趣。
③ it作形式主语时，还常用于 “It takes（took／will take）sb．some time（money）to do sth. ” 句型中。
It took me more than an hour to do my homework yesterday evening．昨天晚上我做作业用了一个多小时。
It will take us a long time to walk there．步行去那儿要花费我们很长时间。
(3) 动词不定式与疑问词how， what，when，where， which等连用构成不定式短语，也可作主语。如：
① How to use the computer is the question．如何使用计算机是个问题。
② Where to go has not been decided．去哪儿还没有定下来。
2．作宾语
① 常与不定式连用作宾语的动词有：want, like, begin, start, choose, forget, remember, need, would like, decide, ask, hope, wish, offer, fail, plan, learn, pretend,
refuse, manage, help, agree, promise, prefer等，如：
Most of us like to watch football matches.
Please remember to post this letter.
I plan to buy a new computer.
② 动词不定式作宾语时，如果他后面有宾语补足语，常用it作形式宾语，而真正的宾语即不定式放在宾补后面。
句型结构为：主语 + 谓语 + it + 宾语补足语 + 动词不定式
I found it easy to make a paper plane.
I found it difficult to solve the problem.
He feels it his duty to help the poor.
We find it necessary to help the blind.
③ 在英语中有些动词如：know, wonder, decide, learn等词后可接“疑问词+不定式”作宾语
Please show us how to do it.
I can’t decide where to go.
The boy didn’t know how to use the computer.
3．作宾语补足语
a．tell，ask，want，order，teach，invite，warn，wish，help，get，wish，help等词后面常接不定式作宾补。如：
I tell him not to go there by bus．
Edison's mother taught him to read and write．
b．let，make，have，see，hear，feel，watch， notice后面接不带to的不定式作宾补。如：
The boss makes them work 16 hours a day．
I heard her sing in the next room．
提示：若变成被动语态，在上述结构中，不定式符号to要加上。如：
They are made to work 16 hours a day by the boss．
She was heard to sing in the next room．
4．作定语：放在被修饰的名词、代词后面
① 不定式作定语往往放在被修饰词的后面，作后置定语
I have nothing to say about that thing.
The next bus to arrive is at 7:45.
Reading aloud is the best way to learn English.
② 与被修饰词之间有动宾关系，如果是不及物动词需要加介词，如：
I have a small bedroom to live in.
Have you got some pens to write with？
Would you please give me some paper to write on.
Could you pass me a pen to write with.
③ 与被修饰词之间有动宾关系，同时与句中其他词之间又有逻辑上的主谓关系时，尽管有被动意义，却仍然用主动。
Do you have anything to say on this problem （anything与say之间是动宾关系；并且和you存在主谓关系）
Would you mind giving me something to drink （drink和something之间是动宾关系；同时和you之间存在主谓关系）
④ 与被修饰词之间有动宾关系而不存在主谓关系，则需用被动语态：
Do you have anything to be taken to your mum （take与anything之间存在动宾关系；但是take 不是you发出的，所以不存在主谓关系）