不定式和动名词

动词不定式和动名词的句法功能比较 一, 作主语 1. 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： ① lt+be+ 名词 +to do It's our duty to take good care of the old. ② It takes sb + some time +to do How long did it take you to finish the work ③ It+be+ 形容词 +for sb +to do It is difficult for us to finish writing the composition in a quarter of an hour. ④ It+be+ 形容词 +of sb +to do It is stupid of you to write dow n everyth ing the teacher says. ⑤ It seems(appears)+ 形容词 +to do It seemed impossible to save mon ey. 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's kind of you to help me with my En glish.=You are kind to help me with my En glish. 2•动名词作主语

Lear ning without practice is no good. 动名词作主语时，也常用It句式.如： ① It's +no good(no use, fun, a pleasure, a waste of time)+doing … It's no good readi ng in dim light. It's no use sitting here waiting. ② It's+形容词+do ing It's dan gerous swim ming 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，女口 :It's important for you to keep fit. ③ There is no + doing There is no say ing what will happe n n ext. 在这一结构中，动名词后常带宾语，相当于"It's impossible to 结构. 3•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 prete nding that you did n't know the rules.

二, 作宾语 1. 不定式作宾语

① 以下动词后 ,只能跟不定式作宾语 .女口:agree, ask, aim, arran ge, choose, decide, dema nd, expect, fail , help, hope, lea n, long, man age, offer, pla n, prepare, prete nd, promise, refuse, wish等，这些词大部分可接that引导的从句.如： I decided to ask for my money back. I decided that I would ask for my money back. When our visit to the farm was over, we expected to start back on foot. When our visit to the farm was over, we expected that we would start back on foot.

② 当复合宾语中的宾语是不定式时 ，先用形式宾语it代替不定式，把不定式置于补语之后，即: 主语+动 词+it+补语+to do句式.如：

We think it quite importa nt for us to lear n a foreig n Ian guage well. He feels it his duty to help the poor.

③ 介词 but, except, besides +to do(do) 在这种句型中，如介词前有动词do,后面应接不带to的不定式；如无do,则接to不定式，即带 do不带to,带to不带do.如：

The en emy soldiers had no choice but to give in. On Sun day after noon I had nothing to do but watch TV. 2•动名词作宾语

① 以下动词后，只能接动名词作宾语，如:admit,即preciate, consider, delay, enjoy, finish, keep, imagi ne, mind, miss, practise, resist, risk, save, suggest, don't mind, give up, in sist, on, put off 等.女口: I suggest spe nding our summer vacati on in a seaside tow n. You must give up smok ing, for it does too much harm to your health.

② 动名词作介词的宾语 I should go to atte nd the birthday celebrati on in stead of stay ing at home. What about in vit ing Li Jun to make a speech 动名词前的介词有时可以省略 ，如:have difficulty(i n)doi ng, have no trouble(i n)doi ng, lose no ti me(in)doing, prevent/stop …(from)doing, there is no use(in)doiig 等. 3. 部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变.如:begin, continue,

start, hat e, like, love, n eed, require, want 等.

在need, require, want 后接-ing形式，表示被动意义 也可接不定式，但要用被动形式，如:Your han dwriti ng n eeds improvi ng (to be improved). hate, love, like 接不定式表示特定的未来事 件,接动名词表示目前 正在进行的活动或一般的行为 . 在下列情况下，一般要用不定式： ① hate, like, love 前有 would(should) 时,女口 :l'd like to have a cup of coffee. ② 当谓语动词 begin, continue, start 等是进行式时 ,女口:The students are starting to work on the difficult maths problem. ③ begin, continue, start 与 know, understand 等状态动词连用时 ,女口 :I soon began to un dersta nd what was happe ning.

4. advise, allow, encourage, forbid, permit 等动词后接动名词作宾语 ,或带不定式作宾语补

足语.如：

Our teachers don't permit our swim ming in the lake. Our teachers don't permit us to swim in the lake. 5•部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用•

① forget, remember, regret 后接不定式，表示现在或未来的动作，接动名词表示动作已经发生 如：

Don't forget fo post the letter for me. Have you forgotte n meeti ng her in Beiji ng Airport Remember to close the win dows before you leave. I remember writing him a letter a year ago. We regret to tell you that all of you are not in vited to atte nd the meet ing. They regretted orderi ng these books from abroad.

② mea n to do 打算做某事 doing 意味着 ..... I meant to catch up with the early bus. This means wast ing a lot of mon ey. ③ try to do设法尽力做某事