1、,语法补充动词不定式,survival of the fittest适者生存 贵阳市乌当中学 高力超,一、动词不定时的用法要点(一)作主语1. 不定式作主语时,往往放在谓语之后,用it作形式主语。To see is to believe.It is not east to learn English well.2. 不定式的复合结构作主语。例如:It is brave of you to do that. (=You are brave to do that.)It is easy for you to do that. (=For you to do that is easy.),(1) 下
2、列表示人物特征的形容词同of后的名词或代词关系密切,有意义上的主表关系,常of与搭配:brave, careful, careless, clever, considerate, cruel, foolish, good, honest, kind, nice, right, rude, stupid, silly, thoughtful, wise, wrong, etc. 例如:It was very kind of you to come to help me.=You were very kind to come to help.,(2) 下列表示事物性质的形容词同for后的名词或代词
3、关系不密切,没有意义上的主表关系,但与句中的不定式结构关系密切,有意义上的主表关系,常与for搭配:easy, hard, heavy, necessary, impossible, possible, difficult, etc. 例如:It is hard for him to get rid of his bad habits.=For him to get rid of his bad habits is hard.,(二)作宾语1. 不定时做宾语时,往往跟在某些及物动词后面,常见的有:afford, agree, ask, decide, desire, expect, fail,
4、 hope, manage, promise, pretend, plan, intend, refuse, wish等。2. 动词不定式作动词tell, show, explain, understand, teach, learn, advise, discuss等词的宾语时,前面常带疑问词。即疑问词(how, when, where, what, who) + to do.,例如:He showed us how to do the work.Please tell us what to do next.(三)定语1. 作定语的不定时如果是不及物动词,或者不定式所修饰的名词或代词是不定式
5、动作的地点、工具等,不定式后面须有相应的介词.如:The Browns have a comfortable house to live in.,但是,不定式所修饰的名词如果是time, place或way时,不定式后面的介词习惯上省去. 如:He had no money and no place to live (in).We found a way to solve this problem (in).2. 当作定语的不定式所修饰的名词或代词是不定式动作的承受着时,不定式既可以用主动语态,也可用被动语态,但其含义有所不同.试比较:,Have you anything to send? 你
6、有什么东西要寄吗?(不定式to send的动作执行者是“你”)Have you anything to be sent? 你有什么要(我或别人)寄的东西吗?不定式to be sent的动作执行者是“我”或“别人”.3. 用不定式作定语的几种情况:不定式表将来:I borrowed some books to read during my holiday.,用来修饰被序数词、最高级或no, all, any等限定的中心词。如:He was the best man to do the job.She was the first woman to win the gold medal in the
7、 Olympic Games.用来修饰的词是抽象名词,常见的有:ability, chance, idea, fact, excuse, promise, answer, reply, attempt, belief, way, reason, moment, time,等 如:Do you have the ability to read and write English?I have no chance to go sight-seeing.,(四)作状语 1. 目的He sat down to have a rest.=He sat down in order/so as to hav
8、e a rest.=In order to have a rest, he sat down.2. 结果He woke up to find everybody gone.3. 在某些形容词作表语,表示喜、怒、哀、乐等后跟不定式表示原因。如:I am very glad to see you.4. 在带有enough或too的句子里,也常用不定式作状语,表示程度。如:,He was too excited not to say a few words.他太激动了,不会不讲几句话的。He is old enough to go to school. 他到上学年龄了.5. 有时可以表示条件To l
9、ook at him, you would like him.6. 可以作独立成分修饰全句。To tell you the truth, I have got no money about me.(五)不定式的主动和被动1. 不定式修饰的名词或代词和不定式逻辑上构成主谓关系时,不定式往往用主动形式。如:Do you have a knife to cut the watermelon?(A knife cuts the watermelon.),2. 不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系,又和该句主语构成逻辑上的主谓关系时,不定式常用主动形式。如:She has a siste
10、r to look after. (She looks after her sister.)3. 不定式做表语形容词的状语,和句中主语构成逻辑上的动宾关系时,不定式多用主动形式;这是因为人们往往认为形容词后省去了for sb.如:This book is difficult (for sb.) to understand.,4. 在there be结构中,当说话人考虑的是必须有人去完成某件事时,不定式用主动形式; 如果说话人强调的事情本身必须被完成,则用被动形式.如:There is a lot of work to do. (Someone has to do the work.)There
11、 is a lot of work to be done. (The work has to be done.)注意下面两个句子的含义不同点:There is nothing to do.(无事可做,感到十分乏味)There is nothing to be done.(某东西坏了,无法使之恢复正常。),(六)不定式中的to是否省略1. 感官动词feel, hear, listen to, see, look at, notice, observe, watch及使役动词 have, let, make等动词后,不定式不带 to,但是,当这些动词变成被动语态时,动词不定式要加上to。如:A c
12、omputer does only what thinking peoplehave it do.计算机只做人们让它做的事。-Mum, why do you always make me eat an egg every day?-To get enough protein and nutrition as you are growing up.,2.不定式用作介词 but和except的宾语时,如果其前有do的某种形式,不定式不带to,否则不定式要带to。如: Sandy could do nothing but admit to his teacher that he was wrong.
13、I can do everything around the house except cook. We have no choice but to fight to win or to die.注意在but构成的习惯用语中不带to: can not help but do不得不;can do nothing but do; can not choose but do; can not doanything but do 只能做。,3. 当两个两个或多个带to的不定式由并列连词and或or连接在一起时,第二个(及其后的)不定式中的to常可省略。但是,如果不定式之间,不是表示并列关系而是表示强烈
14、的对比关系,或者在不用and和or连接时,则第二个不定式前的to不能省略。如:The purpose of new technologies is to make life easier, not to make it more difficult.发展新科技的目的是使生活比恩的轻松,而不是使之麻烦。I want him to write these sentences down and not to translate them into Chinese.(前后对比关系),4. 含有do的名词性从句作句子的主语,或者是all/thing + 定语从句时,其后作表语的不定式 可以带to,也可以
15、不带to,否则不定式要带to。如:What he wants to do is (to) travel to Beijing on the National Day. All I want to do is (to) help my students improve their English level.,5. 在情态动词如:had better, would ratherthan, might as well之后不用to。动词help后 to可带可不带。Rather than ride on a crowded bus, he always prefers to ride a bicycle.Youd better do your homework at once.,Thank you!,Happy New year!,