8下Unit4语法知识点讲解与练习

最新牛津译林版8下Unit 4语言点知识点讲解与练习本单元语法知识一、“特殊疑问词＋动词不定式”的用法归纳（一）由两部分构成：疑问词和动词不定式（wh-+to do）。

疑问词部分包括疑问代词who, whom, what, which和whose以及疑问副词when, where和how。

此外，连接词“whether”也适用.它主要具有以下几种功能：⑴当主语，如：● When to hold the meeting has not yet been decided.● Where to live is a problem.⑵当宾语，常接在forget, find out, discuss, decide, tell, teach, know, learn, wonder, remember等动词之后作宾语如：● We must know what to say at a meeting.● He could not tell whom to trust.● Do you know how to play bridge?⑶当表语，如：● The problem i s where to find the financial aid.● The question is who to elect.⑷当名词同位语，如：● Tom had no idea which book to read first.● The question whether to confess troubled the girl.⑸用于宾语补足语,双重宾语。

某些动词后可接“sb.+ 疑问词+ 不定式”构成的双重宾语，这类动词常用的有advise, ask, show, teach, tell等如：● I can tell you where to get this book.● I ask her how to learn English.● He will advise you what to do.● Will you show me how to use the machine?(6) 作介词宾语：某些介词后面可接"疑问词＋不定式"作宾语，这类介词常用的有about, as, from, in, of, on, with等。

例如：He has no idea of how to answer this question. 他不知道怎样回答这个问题。

Della had only $1.87 with which to buy Jim a present. 德拉仅有$1.87为来吉姆买一件礼物。

(which是关系代词)You have a number of topics from which to choose. 你有很多题目可以选择。

(which是关系代词)（二）“特殊疑问词＋动词不定式”这种结构可以把复合句转为简单句。

如：I don’t know what I’ll do next. = I don’t know what to do next.The doctor told him when he should take the medicine. = The doctor told him when to take the medicine.同样，因为“特殊疑问词＋动词不定式”这种结构相当于一个名词性从句，所以可用同等成分的从句代替，从而把简单句转换为复合句。

改写时只需在疑问词后加上适当的主语，并把不定式改为适当的形式的谓语即可。

如：Which to choose is important. = Which we should choose is important.The question is where to go. = The question is where we should go.（三）“特殊疑问词＋动词不定式”这种结构可构成独立问句。

如：What to do? 怎么办？How to get rid of the trouble? 如何摆脱困境？按照英语语法的习惯，疑问副词why 后不直接跟动词不定式，如：误：I don’t know why to choose that dictionary.正：I don’t know why you must choose that dictionary.但它可以接不带to的动词不定式，即动词原形，构成why do sth./ why not do sth. 肯定形式是表示某动作是不必要的或没有意义的，而否定形式是表示向某人提建议和表达看法，相当于祈使句。

Today is Sunday. Why not go out to relax yourself?Why pay more at other shops? We have the best value.练习一：( )1.I have no idea when _________ her the bad news.A. will tellB. tellingC. tellD. to tell( )2. ---Will you please show me how to do the role-play exercise?---Sure. Now let me tell you ________ first.A. which to doB. how to doC. when to doD. what to do( )3. I need your help because I don’t know ________.A. how to do itB. how to doC. what to do itD. what should I do( )4.---How are you feeling here?---It’s quite hot. I don’t know ________ to go or stay.A. howB. whenC. whetherD. where( )5.---I don’t know ________ to do with this maths problem. It’s too hard.--- You can ask your classmates or teachers for help.A. whichB. howC. whatD. when( )6. ---Millie, could you give me some advice? I don’t know ________.--- Why don’t you wear this red shirt?A. when to wearB. what to wearC. how to wearD. where to wear( )7. I’m going on a field trip but I haven’t decided________.A. what to doB. to do whatC. where to goD. to go where( )8 ---This physics problem is too difficult. Can you show me ________，Wang Lin？---Sure.A. what to work it outB. what to work out itC. how to work it outD. how to work out it ( )9. Excuse me. Would you please tell me ________ buy a digital camera？A. what toB. where toC. what I canD. where can I( )10. There isn't any difference between the two. I really don't know ________.A. where to chooseB. which to chooseC. to choose whatD. to choose which二、动词不定式做宾语补足语(1)常接带to的动词不定式作宾语补足语的动词有：ask, tell, want, teach, wish等；(2)接不带to的动词不定式作宾语补足语的动词有：see, watch, hear, make, let advise, allow, ask, beg, command, tell, invite, force, oblige, get, help, encourage, persuade, permit, remind, request, order, warn, cause等。

例如：I often see him play football.She often asks me to help her.We don't allow such things to happen again.Most of the parents agree to forbid their children to smoke.She asked me to answer the phone in her absence.Please remind me to leave her this note.She requested him to go with her.（3）用不定式作宾语补足语的几种说明：①help后面作宾语补足语的动词不定式可以带to也可以不带to。

如：I often help my mother (to) do some housework.②在使役动词后作宾语补足语，不定式不带to。

有些动词跟不定式作宾语补足语时省去了to，这些动词有：一感二听三让四观看。

一感：feel二听：hear, listen to三让：let, have, make 四观看：notice, see, watch, look at这类动词有：make, let, have等。

转为被动语态时，其后通常都用带to的不定式（have没有被动语态）。

例如：What would you have me do?Let him do whatever he wishes to do.Though he had often made his little sister cry, today he was made to cry by his little sister.（4）不定式作宾语补足语的有以下八种类型：①许多动词可跟一个宾语+ to do…构成句子，句中的不定式作宾语补足语；否定形式为“动词+宾语+not to do…”。