语法（非谓语动词）I. 动词不定式和动名词的构成形式动词不定式是由“ to + 动词原形”构成；动名词由动词+ing构成。
主动式有：一般式、进行式、完成式和完成进行式；被动式有：一般式、进行式和完成式。
时态主动被动语态动词不定式to do to be done一般式动名词doing being done动词不定式to be doing to be being done 进形式动名词doing being done动词不定式to have done to have been done 完成式动名词having done having been done动词不定式to have been doing完成进形式动名词having been doingII. 动词不定式、动名词用法要点讲解一．做主语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 doIt's our duty to take good care of the old.②It takes sb + some time + to doHow long did it take you to finish the work?③It＋be＋形容词＋for sb＋to doIt is difficult for us to finish writing the composition in a quarter of anhour.④It＋be＋形容词＋of sb＋to doIt is stupid of you to write down everything the teacher says.⑤It seems(appears)＋形容词＋to doIt 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's kind of you to help me with my English.=You are kind to help me with my English.⒉动名词做主语Learning without practice is no good.动名词做主语时，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＋doingIt'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's important for you to keep fit.③There is no + doingThere is no saying what will happen next.There is no denying that he has stolen the bike.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, lean, long,manage, offer, plan, prepare, pretend, 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 backon 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 important for us to learn a foreign language 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 enemy soldiers had no choice but to give in.On Sunday afternoon I had nothing to do but watch TV.⒉动名词作宾语①以下动词后，只能接动名词作宾语，如：admit, appreciate, consider, delay, enjoy, finish, keep, imagine, mind, miss, practise, resist, risk, save, suggest,don't mind, give up, insist on, put off等。
如：I suggest spending our summer vacation in a seaside town.You must give up smoking, for it does too much harm to your health.②动名词作介词的宾语I should go to attend the birthday celebration instead of staying at home.What about inviting Li Jun to make a speech?动名词前的介词有时可以省略，如：have difficulty(in) doing, have notrouble(in) doing, lose no time (in) doing, prevent/stop…(from)doing, there is no use(in)doing等。
⒊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, hate, like, love, need, 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 handwriting needs improving (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：①hate, like, love前有would(should)时，如：I'd like to have a cup of coffee.②当谓语动词begin, continue, start等是进行式时，如：The students are starting to work on the difficult math problem.③begin, continue, start与know, understand等状态动词连用时，如：I soon began to understand what was happening.⒋advise, 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 swimming in the lake.Our teachers don't permit us to swim in the lake.⒌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。
①forget, 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 to post the letter for me.Have you forgotten meeting her in Beijing Airport?Remember to close the windows before you leave.I remember writing him a letter a year ago.We regret to tell you that all of you are not invited to attend the meeting.They regretted ordering these books from abroad.②mean to do 打算做某事mean doing 意味着……I meant to catch up with the early bus.This means wasting a lot of money.③try to do 设法尽力做某事try doing 试着做某事You should try to overcome your shortcomings.Try working out the physics problem in another way.④stop to do 停下一件事去做另一件事（不定式作目的状语）stop doing 停止做某事On the way to the airport, I stopped to buy a paper.You'd better stop arguing and do as you are told.⑤can't help doing 禁不住……can’t help to do不能帮助干……They couldn't help jumping up at the news.Sorry I have lots of work to do. So I can't help to make up the room for you.⑥go on to do 做不同的事或不同内容的事go on doing 继续不停地做某事，指同一动作的继续He went on to talk about world situation.他接着又谈了世界形势。
