自考英语二语法U-8不定式.doc

本课主要语法点：动词不定式在句子中不能作谓语，而是担任其他语法功能的动词，叫做非谓语动词。非谓语动词包括动词不定式，分词和动名词。1.不定式的语法功能：不定式具有名词、形容词和副词的特征，因此他在句中可以作主语、表语、宾语、宾补、定语和状语。1)作主语如：To speak English well is not an easy job. 说好英语不是一件容易的事情。动词不定式作主语时，为了保持句子的平衡，往往用it作形式主语，而把不定式短语放在谓语动词之后。如：It is important to master English grammar. 掌握英语的语法是重要的。2)作表语如：Our plan is to set up another middle school for the children. 我们的计划是为孩子们再建一所学校。 His ambition is to become a successful scientist. 他的抱负是要成为一名成功的科学家。3)作宾语如：They decided to change their mind. 他们决定改变主意。 I cant afford to live in a detached house. 我住不起独门独院的房子。注：a)不定式短语作宾语时，如果还有宾语补足语，往往把不定式短语放在宾语补足语后面，而用it作形式宾语。如：I find it interesting to study English. 我觉得学英语很有趣。b)动词不定式也可以作某些形容词短语的宾语。这些形容词有：ready, eager, anxious, able, sure, glad, afraid, pleased等。如：They are anxious to learn how to swim. 他们渴望学会游泳。c)动词不定式一般不作介词的宾语，但是不定式之前如有疑问词，就可以作介词的宾语。如：Professor Wang gave some advice on how to learn a foreign language. 王教授给了一些如何学习外语的建议。d) 有些动词可以跟疑问词+不定式作宾语如：I dont know what to do next. 我不知道下一步该做什么。4)作宾语补足语动词不定式可用作复合宾语中的宾语补足语。如：My English teacher advised me to buy a better dictionary. 我的英语老师建议我买一本好的词典。注：在feel, hear, listen to, look at, observe, see, watch, make, have, let等动词后面，复合宾语中动词不定式的标记to通常被省略。动词help后面的to可以省略也可以保留。如：I saw her enter the cinema. 我看见她进了电影院。 We must have someone repair the computer. 我们必须让人来修这台电脑。 He helps the little girl (to) finish her homework everyda. 他每天都帮助这个小女孩完成她的家庭作业。5)作定语动词不定式作定语放在所修饰的名词或代词之后。如：Her desire to win was apparent. 她的求胜愿望显而易见。 She was the only one to get a scholarship. 她是唯一得到奖学金的人。注：a)作定语的不定式如果是不及物动词，或者不定式所修饰的名词或代词是不定式动作的地点、工具， 不定式后面须加相应的介词。如：She is looking for a room to live in. 她在寻找一间房子住。(live是不及物动词，后面加相应的介词) I need a pen to write with. 我需要一支笔写字。(pen是write动作的工具，在write后面加介词)但是如果不定式修饰的名词是time, place或way, 不定式后面的介词习惯上省去。如：He had no place to live. 他没有居住的地方。 Thats no way to talk. 不应这样谈话。b)在there+be这一句型中，动词不定式作定语时可能出现动词不定式的被动式，其含义和主动式基本相同。如：There are many books to read/ to be read. 有好多书要读。但是当说话人考虑的是必须有人去完成某件事情时，不定式用主动形式，如果说话人强调的是事情本身必须完成，则用被动式。如：Theres nothing to do. 意为无事可做，感到无聊。 Theres nothing to be done. 意为某东西坏了，无法使之恢复正常。c)被only, last, next，序数词，最高级修饰的名词常用不定式作定语。如：The next train to arrive is from New York. 下一列到达的火车是从纽约开来的。 Clint was the only person to survive the air crash. Clint 是这次空难事故中唯一的幸存者。6)作状语a)动词不定式作目的状语：如：He went to America to learn English. 他去美国学习英语。为了强调动词不定式所表示的目的时，动词不定式可以用in order to或so as to.如：She reads China Daily every day in order to/so as to improve her English. 她每天读中国日报提高她的英语水平。in order to 为于句首或句中均可，so as to不能为于句首。b)动词不定式作结果状语：不定式作结果状语时，往往仅限于几个具有终止含义的动词，learn(得知),find(发现)，see(看见)，hear(听见)等。如：He returned home to learn his son had gone to the countryside. 他回家后才知道他的儿子已去了乡下。不定式用在tooto和enough结构中表示结果如：He is old enough to join the army. 他够参军的年龄了。 He is too short to reach the top of the shelf. 他太矮了，够不着书架的顶层。某些形容词如：anxious, delighted, easy, kind, pleased, ready, willing 等，在tooto结构中，没有否定的含义，而是表示肯定。如：He is too ready to find fault. 他老是爱挑毛病。在not, only, all, never, but等后的tooto结构，too的含义为very,不定式没有否定含义。如：It is never too late to learn. 活到老，学到老。动词不定式和only连用时，表示未预料到的结果。如：He went to the station hurriedly only to find the train had left. 他匆匆地赶到车站，却发现火车已经离开了。2.动词不定式的复合结构动词不定式的复合结构for+名词或代词宾格+动词不定式，在这种结构中，for后面的名词或代词是不定式的逻辑主语。如：It is necessary for us to learn from each other. 我们必须互相学习。(不定式作主语) What we want is for you to understand the matter clearly. 我们所希望的是你更清楚地了解这件事。(不定式作表语) We consider it necessary for him to do the job alone. 我们认为很有必要他独自做那项工作。(不定式作宾语) There is a lot work for us to do. 有很多工作要我们去做。(不定式作定语) The text is too long for us to learn by heart. 课文太长，我们背不下来。(不定式作状语)注：有些表示人或事物性质、特征的形容词的不定式复合结构是of+名词或代词宾格+动词不定式如： It is very kind of you to help him every day. 每天帮助他，你真好。 It is brave of you to do that. 你那样做真勇敢。3.疑问词what, who, which, when, where, how和连接词whether之后，可以跟带to的不定式，构成一个特殊的动词不定式短语，可以在句中作主语，宾语和表语。如：How to solve the problem is very important. 如何解决这个问题是很重要的。(主语) He didnt know what to say. 他不知道该怎么说。(宾语) The question is where to find the source of water. 问题是在什么地方能找到水源。(表语)4.不带to的不定式1)在feel, hear, listen to, look at, notice, observe, see, watch, let, have等动词后面，动词不定式作宾语补足语，动词不定式符号to通常省略。2)在would ratherthan, would soonerthan, rather than, had better等结构中如：I would rather go than stay. 我宁愿走不愿意留下。 He insisted on going back to his work rather than stay in hospital. 他坚持要返回到工作岗位，而不再住院。3)在以why引导的疑问句中不带to。如：Why spend such a lot of money? 为什么花那么多钱?4)在cannot but, cannot choose, cannot help but之后的不定式不带to.如：I cannot but admire his courage. 我不得不钦佩他的勇气。5) 不定式动词在介词but, except, besides后面时，如果这些介词之前有行为动词do的各种形式，那么，这些介词后面的不定式不带to, 否则要带to。如：The boy would do nothing but cry. 这个男孩只是哭。 I have no choice but to accept the fact. 除了接受这个事实之外，我别无选择。6)某些习语中，如：make believe(假装)，let go (放开，释放)，hear say(据说)，go hang (忘却)等。如：The children are making believe that they are princes and princesses. 孩子假装他们是王子和公主。7)两个动词不定式由and, or 或than连接在一起，为了避免重复，第二个动词不定式可以省去。如：Id like to lie down and go to sleep. 我想躺下睡觉。 但是如果是两者的对照，后面的不定式不省to.如：It is better to laugh than to cry. 笑比哭好。第二部分 巩固练习用括号中动词的适当形式填空1.The boy was made _ (sing) the song once again.2.Dont make children _ (work) too hard.3.They would rather _ (die) than _ (surrender).4.He could not choose but to_ (love) her.5.She could do nothing but _ (change ) her name under the circumstances.6.He had his