动词不定式和动名词的句法功能比较-7.doc

动词不定式和动名词的句法功能比较： ??? （附图 {图}） ??? 一、作主语 ??? ⒈不定式作主语 ??? 动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种： ??? (1)把不定式置于句首。如： ??? To get there by bike will take us half an hour. ??? (2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。 如： ??? ①It＋be＋名词＋to do ??? It‘s our duty to take good care of the old. ??? ②It takes sb+some time+to do ??? How long did it take you to finish the work? ??? ③It＋be＋形容词＋for sb＋to do ??? It is difficult for us to finish writing the compositionin a quarter of an hour. ??? ④It＋be＋形容词＋of sb＋to do ??? It is stupid of you to write down everything the teachersays. ??? ⑤It seems(appears)＋形容词＋to do ??? It seemed impossible to save money. ??? 在句型③中，常用表示客观情况的形容词，如： difficult,easy,hard,important,impossible,necessary 等；在句型④中，常 用 careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid ,wise等 表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句 式有时相当于Sb is＋形容词＋to do句式 ，如：It’skind of you to help me with my English.=You are kind to helpme with my English. ??? ⒉动名词作主语 ??? Learning without practice is no good. ??? 动名词作主语时，也常用It句式。如： ??? ①It‘s +no good(no use,fun,a pleasure,a waste of time)+doing… ??? It’s no good reading in dim light. ??? It‘s no use sitting here waiting. ??? ②It’s＋形容词＋doing ??? It‘s dangerous swimming in the sea in windy days. ??? 这样用的形容词有expensive,nice,tiring等，但important,necessary则 不适用于这种结构，应用不定式 代替，如：It’simportant for you to keep fit. ??? ③There is no+doing ??? There is no saying what will happen next. ??? 在这一结构中，动名词后常带宾语，相当于"It‘s impossible to…"结构。 ??? ⒊动词不定式和动名词作主语的区别 ??? ①不定式作主语经常表示具体动作，常与特定的动作执行者联系在一起；而 动名词作主语经常表示抽象动 作，经常不与特定的动作执行者联系在一起。如： ??? It’s no good eating too much fat. ??? It‘s no good for you to eat so much fat. ?? ?②动名词结构作主语，可以用名词或代词属格形式作逻辑主语。如： ??? It’s no use your pretending that you didn‘t know the rules. ??? 二、作宾语 ??? ⒈不定式作宾语 ??? ①以下动词后，只能跟不定式作宾语。如： agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lea n,long,manage,offer,plan,prepare,pretend,promise,refuse,wish等，这些 词大部分可接th at引导的从句。如： ??? I decided to