作者：李洪涛 赵军

不定式与动名词都可以在句中作主语、宾语、表语和定语,但用法不尽相同。


一、作主语


一般情况下,不定式与动名词作主语可以互换,也常常可以用it充当形式主语,而把不定式和动名词放在句子的后半部分。但二者也有区别,不定式常常指某次具体的、将要发生的行为;而动名词则表示一般的、抽象的行为。例如:


To save money now is not easy. 现在攒钱不容易。


Saving money is a good habit. 攒钱是个好习惯。


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1. ________ to sunlight for too much time will do harm to one\'s skin.


A. Exposed B. Having exposed


C. Being exposed D. After being exposed


二、作宾语


有些动词后只能跟不定式作宾语,不能跟动名词作宾语;有些动词后常跟动名词作宾语,不能跟不定式作宾语;有些动词后跟不定式和动名词作宾语皆可,但意思不同(详见本报第2期第1面《如何使用动名词(http://www.xmyuanda.com》 ),同学们应熟记这几组词。另外还要熟记下面几点:


1)下列短语中的to是介词,其后跟动名词,不跟不定式。


be(get) used to习惯于;look forward to盼望;pay attention to注意;get down to开始认真做;lead to通向、导致;prefer doing ... to doing ...宁愿做......而不愿做......;stick to坚持;devote one\'s life(time, oneself) to献身于、致力于;object to反对;in addition to ...除......之外;on the way to ...在去......的路上、正要成为......;等等。


2)不定式除可用在except, but, besides等后作宾语之外,一般不用作介词宾语。此时,不定式能否省略to,取决于其前是否有行为动词do或其相应形式。有则省略,无则不能省略。例如:


She did nothing but wash some clothes that day. 那天她除了洗一些衣服之外什么也没做。


We had no choice except to walk home. 除了走着回家我们别无选择。


3) 动名词除了其一般式doing,还有完成式having done以及一般式的被动形式being done和完成式的被动形式having been done;动名词前可以加上逻辑主语,构成动名词的复合结构:sb.\'s doing。例如:


I\'m sorry for not having kept my promise.非常抱歉,我没能遵守诺言。(not having kept my promise发生在am sorry之前)


Do you mind Mary being left alone at home?你介意玛丽被单独一个人留在家里吗?


4) 不定式的完成式to have done表示在谓语动词之前已经发生的动作,而不定式的一般式to do表示动作将要发生。不定式还有其被动形式:to be done(表示将来的被动动作)和to have been done(表示过去的被动动作)。


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2. Mr. Reed made up his mind to devote all he had to ________ some schools for poor children.


A. set up B. setting up


C. have set up D. having set up


三、作表语


不定式与动名词作表语时的区别与作主语时相同。例如:


My job is teaching English. 我的工作是教英语。(泛指,多次性抽象行为)


Your task is to go and help the farmers.你的工作是去帮助那些农民。(特指,一次性具体行为)


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3. Having a trip abroad is certainly good for the old couple, but it remains ________ whether they will enjoy it.


A. to see B. to be seen C. seeing D. seen


四、作定语


不定式多为后置定语,动名词多为前置定语;不定式多表示将来的动作,动名词只能表示事物的属性、用途等。例如:


He is looking for a room to live in.他正在找一间房子去住。


Take these sleeping pills and you\'ll sleep better. 吃了这种安眠药,你会睡得更好。


注意:不定式作定语时通常与其前的名词(代词)构成动宾关系。如果作定语的不定式是不及物动词,其后通常要加上相应的介词。例如:


Please give me a knife with which to cut.


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4. There are five pairs ________ , but I\'m at a loss which to buy.


A. to be chosen B. to choose from


C. to choose D. for choosing


答案:1-4 CBBB