如题所述
1.在what引导的感叹句中。如：
What a difficult situation he is in ！他处境多困难啊！
What a great plan you are carrying out ！你们实施的这项计划真伟大！
2.在以who，whom，what，which，whose等引导的就介词宾语或定语提问的特殊疑问句中。如：
Who are you working with ？你和谁一起工作？
Which subject are you interested in ？你对哪一门学科感兴趣？
3.在be／seem／appear＋形容词＋不定式结构中，动词不定式结构与句子的主语之间有逻辑上的动宾关系或主谓关系。当其为动宾关系时，动词不定式中的动词应为及物动词或不及物动词加介词构成的相当于及物动词的词组。如：
The man is hard to get along with .那个人很难相处。
This room seems too small for us to live in.这房间对我们而言似乎太小了，不能居住。
常见的这类形容词有：easy，difficult，nice，big，large，hard，light，heavy，interesting，dangerous等。
4.当不定式做定语，且与被修饰的中心词有逻辑上的动宾关系时。如：
She has a lot of things to see to.她有很多事情需处理。
There is nothing to worry about.没有什么可担心的。
5.在“疑问代词＋不定式”结构中。如：
He is wondering what to deal with.他想知道要应付些什么情况。
I don’t know whom to turn to.我不知道向谁求助。
6.在who，whom，what，which，whose引导的宾语从句中。如：
He asked her what she studied English for.他问她学英语的目的是什么。
She wondered whose son the doctor was operating on.她想知道医生在为谁的儿子动手术。
7.在被动结构中，当含有介词的短语动词是一个不可分割的整体时。如：
For this he was often made fun of.为此人们常和他开玩笑。
No one likes to be laughed at.没有人喜欢被人嘲笑。
8.在be worth doing结构中。如：
This topic is worth writing about.这个题目值得一写。
His talk is well worth listening to.他的报告值得一听。
9.在need／want／require＋doing结构中。如：
The young trees need looking after.这些小树需要护理。
The matter requires looking into.这件事需要调查。
10.在定语从句中。如：
Do you know the comrade she was talking to？和她谈话的那位同志你认识吗？
This is the very thing I’m looking for.这正是我在找的东西。
〔练一练〕请在句中横线上填上合适的介词：
1.He is really the little boy（that） Mrs Li is looking________.
2.Now the new machine needs doing_______.
3.The TV play isn’t worth talking too much__________.
4.He was glad to see his son well taken care___________.
5.Doctor Chen is a good example for us to learn__________.
6.The doctor has been sen________________.
7.The grass is too wet to sit__________.
8.He didn’t know what to talk__________.
9.The picture is good to look_________.
10.Can you tell me what you did it________？
希望对你有所帮助
What a difficult situation he is in ！他处境多困难啊！
What a great plan you are carrying out ！你们实施的这项计划真伟大！
2.在以who，whom，what，which，whose等引导的就介词宾语或定语提问的特殊疑问句中。如：
Who are you working with ？你和谁一起工作？
Which subject are you interested in ？你对哪一门学科感兴趣？
3.在be／seem／appear＋形容词＋不定式结构中，动词不定式结构与句子的主语之间有逻辑上的动宾关系或主谓关系。当其为动宾关系时，动词不定式中的动词应为及物动词或不及物动词加介词构成的相当于及物动词的词组。如：
The man is hard to get along with .那个人很难相处。
This room seems too small for us to live in.这房间对我们而言似乎太小了，不能居住。
常见的这类形容词有：easy，difficult，nice，big，large，hard，light，heavy，interesting，dangerous等。
4.当不定式做定语，且与被修饰的中心词有逻辑上的动宾关系时。如：
She has a lot of things to see to.她有很多事情需处理。
There is nothing to worry about.没有什么可担心的。
5.在“疑问代词＋不定式”结构中。如：
He is wondering what to deal with.他想知道要应付些什么情况。
I don’t know whom to turn to.我不知道向谁求助。
6.在who，whom，what，which，whose引导的宾语从句中。如：
He asked her what she studied English for.他问她学英语的目的是什么。
She wondered whose son the doctor was operating on.她想知道医生在为谁的儿子动手术。
7.在被动结构中，当含有介词的短语动词是一个不可分割的整体时。如：
For this he was often made fun of.为此人们常和他开玩笑。
No one likes to be laughed at.没有人喜欢被人嘲笑。
8.在be worth doing结构中。如：
This topic is worth writing about.这个题目值得一写。
His talk is well worth listening to.他的报告值得一听。
9.在need／want／require＋doing结构中。如：
The young trees need looking after.这些小树需要护理。
The matter requires looking into.这件事需要调查。
10.在定语从句中。如：
Do you know the comrade she was talking to？和她谈话的那位同志你认识吗？
This is the very thing I’m looking for.这正是我在找的东西。
〔练一练〕请在句中横线上填上合适的介词：
1.He is really the little boy（that） Mrs Li is looking________.
2.Now the new machine needs doing_______.
3.The TV play isn’t worth talking too much__________.
4.He was glad to see his son well taken care___________.
5.Doctor Chen is a good example for us to learn__________.
6.The doctor has been sen________________.
7.The grass is too wet to sit__________.
8.He didn’t know what to talk__________.
9.The picture is good to look_________.
10.Can you tell me what you did it________？
希望对你有所帮助
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