with，without +名词+不定式结构

 有这么多工作要做，我不能和你去看电影了。With so much work to do ，I shall not be able to go to the cinema with you

 有他住在家里，我感到十分安全。With him to stay in the house，I feel quite safe

 由于没有东西吃，他饿死了。Without anything to eat，he died of hunger

在“ it is +形容词+ of somebody +不定式”结构中，形容词往往表示人物的性格和特征，如 善良，kind，愚蠢，silly，好的，good，不明智，unwise，聪明，clever，错误，wrong，正确，right，愚蠢，foolish，愚蠢，stupid，粗心，careless，粗鲁，rude，不礼貌，impolite，大胆，bold，体贴，thoughtful，诚实，honest，坏，bad，明智，sensible，调皮，naughty 等。

在“ it is +形容词+ for somebody +不定式”结构中，形容词通常表示事物的性质，如 重要的，important，可能的，possible，不可能的，impossible，必要的，necessary，困难的，difficult，困难的，hard，合理的，reasonable 等。

 难为你这么为我们着想。it 's kind of you to think so much of us   

You are kind to think so much of us

他真不小心，把如此贵重的花瓶打破了。How careless it is of him to break such a valuable vase !

 我很容易看穿他的鬼把戏。it is easy for me to see through his trick  

 For me to see through his trick is easy

 他很难改掉自己的坏习惯。it is hard for him to get rid of his bad habits

 你真好，帮助我学英语。it is good of you to help me with my English    

You are good to help me with my English

 戒烟对你有好处。it is good for you to give up smoking    

For you to give up smoking is good  

动词不定式 to do 通常是不拆开的，但偶尔也可在不定式符号 to 和动词原形之间插入一个副词，构成分裂不定式。

 他病得太重，不能完成那个项目。He was too ill to completely carry out that program

 他已经下定决心再试试这个方法。He has made up his mind to once more try this method

有一些不定式短语可以作状语修饰整个句子，也可被称为插入语。

 说老实话，我们不能确保在森林里能找到那个女孩。to be honest，we are not sure to find the girl in the forest

 坦率地说，我不同意你说的话。to be frank，I don't agree with what you said

用作独立成分的不定式

说老实话to tell you the truth

坦率地说to be frank

首先to begin with

简言之to be brief

长话短说to make a long story short

精确地说to be exact

姑且不说to say nothing of

总而言之to conclude

诚然，固然to be sure

说句对他公道的话to do him justice

可以这么说so to speak

 不定式做后置定语，和被修饰的名词或代词构成逻辑上的动宾关系，但又和该句主语构成逻辑上的主谓关系。

 针对这个问题你有什么要说的吗？do you have anything to say on this question?

 他是一个与其合作起来令人感到愉快的人。He is a pleasant person to work with

 不定式作形容词的宾语，和句子主语构成逻辑上的动宾关系。

 这本书很难理解。The book is difficult to understand

 这把椅子坐起来很舒服。The chair is comfortable to sit on

 There be 结构中，说话人考虑必须有人去完成某件事。

 没什么可担心的。There is nothing to worry about

 没有什么可害怕的。There is nothing to fear

 有许多事情要做。There is a lot of work to do

 有许多事情要做。There is a lot of work to be done

 她有两封信要打。She has two letters to type

 她有两封信要打。She has two letters to be typed

表示虚拟语气的不定式完成式。

 我本希望在火车站接到他，但他未露面。I hoped to have met him at the railway station，but he didn't turn up

 我们原想去看这场比赛的，但票已售完了。We would love to have gone to the match，but the tickets were all sold out

 飞机原计划九点起飞，但出现了一些故障。The plane was to have taken off at 9, but something went wrong

不定式可用于感叹句，含有惊异，不满，惋惜或赞美等感情色彩。

想想，他竟然干出这等事！to think that he should do this !

哦，天哪，看看她的舞蹈！Oh，God，to see her dance !

 想想，所有的钱都被浪费掉了！to think that all the money has been wasted

 在口语中，动词原形 come 和 go 后可接不带 to 的不定式。

 去告诉她吧。Go tell her

 来喝一杯。Come have a glass

 在 why 引起的一些问句中，疑问词直接跟动词原形或 not +动词原形。

 为什么发出这么大的噪音？Why make so much noise?

 为什么不加入我们？Why not join us?

 最好had better，最好had best，宁愿prefers to 宁愿 would rather，宁愿而不愿 would rather   than，宁愿 would sooner，宁愿而不愿 would sooner     than，只能cannot but，只能选择cannot choose but，忍不住cannot help but ，不愿rather than等结构后直接跟动词原形或 not +动词原形。

 你最好听一听老师的意见。You'd better listen to your teacher's opinion

 我们最好马上就请医生来。We had best call for the doctor at once

 我宁愿丽丽负责这件事I would rather Lili took it on  

 她一直在问一些愚蠢的问题。She can't do anything but ask silly questions

 他宁愿骑自行车，也不愿挤公共汽车。Rather than ride on a crowded bus，he always prefers to ride a bicycle

我宁可不睡觉，也不愿错过晚上的课。I would sooner give up sleep than miss my evening class

 他不得不搬到另一条街上去，因为他住的大楼很快就要被推倒。He cannot but move to another street，because his building has to be pulled down soon

 我们情不自禁地钦佩他的勇气。 We cannot help but admire his courage