九年级下册各单元知识点--语法.doc

Unit 1 life on mars 语法1can could may might 来谈论“允许”正式程度非正式的can 用来问朋友做某事是否可以正式的could 经常用来征求陌生人，老人，老师和老板的允许正式而有礼貌的may 通常用于正式语境来征求是否可以做某事。非正式的might 非常有礼貌，但很少用。例句：Can /Could I go to the zoo tomorrow, Mum? Yes,you can. No,you cant. May /Might I use your computer,Mr Wu? Yes ,you may. No, you may not/cant.2由that 引导的宾语从句宾语从句和宾语作用一样，可以放在一些动词如think,believe,know之后，也可以跟在一些形容词后，如certain,sure。例句：Many people believe that robots will do most of our work.3 由if 或者whether引导的宾语从句当表达“是/否”的问题时，我们用if 或者whether来引导宾语从句，在那种情况下，我们通常用称述句语序。例句：Nobody is sure if/whether these plants could produce enough water. We are wondering if/whether we can grow plants on Mars.9B Unit 2 Robots语法 1 由wh-疑问词引导的宾语从句 We can use a wh- words to introduce an object clause when it expresses a wh- question. The word order in the object clause should be the same as that in a statement. 例句： The robot no longer knew when it should cook breakfast. Mr. Jiang did not know what he should do with the robot.特殊疑问句作宾语从句时一定要注意用陈述句语序。时态根据主句而定。（但如果是真理或客观事实则用一般现在时，不需要改变。）特别注意有些特殊疑问句本身就是陈述句语序（因特殊疑问词作主语），如 Who is on duty? Whats wrong with you? Whats the matter with you? What happened to you? 等等。2 “In order to” and “as a result” In order to means with the purpose of. We can use in order to to introduce the purpose of an action. 表示目的，引导不定式；或者表示结果。 例句： In order to have more spare time, I need to buy a robot. I need to buy a robot in order to have more spare time.We use as a result to introduce the result of something.表示结果， 用逗号隔开，接完整句子。 例句： The robot did all the housework. As a result, Mr. Jiang no longer need to get up early.3使用need to We can use need to to talk about something that we have to do. 我们用need to来谈论我们不得不做的事情。 Need做实义动词时，后接不定式。 例句： Mr Jiang no longer needed to do housework because he had a robot. Mr Jiang needs to return his robot to the shop because it is not working,9B Unit3 Asia语法1 Using although-although引导的让步状语从句although相当于though, 两词都是连词，引导让步状语从句。如：-Although/Though shes young, she knows a lot.=Shes young, but she knows a lot.尽管她年龄小，她却懂得很多。-Although/Though he is in poor health, (yet) he works hard.=Hes in poor health, but he works hard.虽然他身体不好，但他还是努力工作。-当加强语气时，我们通常说even though，而不说even although。如：Although/ Though/ Even though she didnt understand a word of what he said, she kept smiling. 尽管他的话她听不懂一个字，她还是一直微笑着。-though可以用于句末，although则不可以。如：She knew all her friends would be there, she didnt want to go, though.她知道她的所有朋友都会出席，但是她自己不想去。注意：让步状语从句通常与一般现在时或一般过去时连用。2 Using unless - unless引导的条件状语从句由于unless具有否定意义，因此它引导的是个否定的条件（如果不）。可以把它看作是ifnot的同义表达手段。如：-Unless he comes = If he doesnt come 如果他不来-Unless you work hard, you will fail. = If you dont work hard, you will fail.如果你不努力工作，你会失败的。注意：unless从句，如同if从句一样，也要用一般现在时代替一般将来时。如：-Unless it rains, well go hiking.如果不下雨，我们将去远足。-Unless he comes, Ill go instead of him.如果他不来，我将代替他去。3 Using so that - so that引导的目的状语从句a.so that引导目的状语从句，从句中通常带有can, could, may, might, should等情态动词，以适用于目的。如：-They worked very hard so that they could finish the work before supper.他们拼命地干，想在晚饭前就把工作干完。-He walked by the side of the road so that he would not be hit by cars.他在马路边行走，以免被车碰了。注意：（1）so that从句如为否定结构，则谓语动词中多用情态动词。b.so that引导的目的状语从句，可转换成in order that引导的目的状语从句。若从句主语与主句主语一致，还可用in order to (do) 或so as (to do) 改成同义简单句。如：They worked very hard so that they could finish the work before supper.= They worked very hard in order that they could finish the work before supper.= They worked very hard in order to finish the work before supper.= They worked very hard so as to finish the work before supper.c.so that引导的状语从句也可表示结果，这时so that从句中根据句意可用或不用情态动词。 如：-They worked very hard so that they finished the work before supper.他们拼命地干，结果他们在晚饭前就把工作干完了。-He got up very late this morning so that he was late for school. 今天早晨他起得很晚，结果他上学迟到了。9B Unit4 语法点 Defining relative clauses & Relative pronouns 定语从句及关系词在复合句中，修饰某一名词或代词的从句叫定语从句。被修饰的名词或代词叫先行词，定语从句一般放在先行词的后面。如：The man who lives next to us is a policeman. You must do everything that I do. 上面两句中的man和everything是定语从句所修饰的词，叫先行词，定语从句放在先行词的后面。引导定语从句的词有关系代词that, which, who(宾格who, 所有格whose)和关系副词where, when、why1.who指人，在从句中做主语(1)The boys who are playing football are from Class One.(2)Yesterday I helped an old man who lost his way.2. whom指人，在定语从句中充当宾语，常可省略。 (1) Mr. Liu is the person (whom) you talked about. (2) The man who/whom you met just now is my friend.3. which指物，在定语从句中做主语或者宾语，做宾语时可省略 (1) Football is a game which is liked by most boys. ( which 在句子中做主语) (2) This is the pen (which) he bought yesterday. ( which 在句子中做宾语)4. that指人时，相当于who或者whom；指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。 (5) The people