北师大版英语八年级上册Unit4 语法辨析-状语从句易错点辨析

1、教育精选语法辨析-状语从句易错点辨析一、目的状语与结果状语从句引导词so that辨析记忆要诀：目的结果（so）that,相貌一样难分开。结果状语so that,主从停顿分两排;目的状语so that,从句之中有情态。主从之间没逗号,一气呵成连起来。注意:so.that结构中,so修饰的短语可置于句首,加强句子语气,主语和谓语动词要倒装。如:So crowded is this bus that I can hardly breathe.车上如此拥挤以至于我几乎喘不动气。8.方式状语从句方式状语从句放在主句之后,用as, just as, as if, as though等引导。as if和a

2、s though引导的从句一般用虚拟语气,但如果从句中所陈述的情况很可能实现,也可用陈述语气。如：The old man runs very fast as if he were a young man.那个老人跑得非常快,好像是个轻人。You may do as you please.你想干什么就干什么吧。9.比较状语从句比较状语从句常用as.as.,than, not so.as.,the more.the more.等词引导。比较状语从句部分常是省略句。如：I know you better than he does.我比他了解你。The more we can do for you,

3、the happier we will be.我们为你做得越多,我们就越高兴。二、as作为从属连词能引导五种状语从句1.引导时间状语从句。as作“当时”解,表示从句和主句的动作同时或几乎同时发生。如：She glanced at me curiously as I opened the door.我开门时,她好奇地瞧了我一眼。（两动作略有先后）As I was coming here, I met your brother.我往这儿来的时候,遇见了你哥哥。（前动作过程中,后动作发生）He stare at me solemnly as I went out of the door.我走出门时,

4、他严肃地注视我。（两个动作同时发生）Jane heard the story as she washed.珍妮边洗衣服边听故事。（两个长动作同时进行）2.引导原因状语从句。as作“由于”“既然”解,着重用事实说明原因。如：As all the seats are full, he stood there.由于座无虚席,他站在那里。3.引导方式状语从句。as作“按照”“如同”解。如：I have changed it as you proposed.我已按照你的建议做了修改。Do it as I do.我怎么干,你就怎么干。这类状语从句中,“it+be” 有时被省略掉。如：As (it was)

5、 expected, the forestation movement rapidly spread.如所预料,植树造林运动迅速地被普遍掀起。4.引导让步状语从句。as作“虽然”“尽管”解。如：Child as she is, she can write good compositions.她虽幼,却能写出好作文。Poor as he was, he was honest.他虽穷,却很诚实。5.引导比较状语从句。前一as是副词（“那样”）,后一as是连词（“像”）。三、as, when, while 用法有何异同as“正当”“在的同时”。when“在时”“当的时候”。while“在期间”“在过

6、程中”。1.在从句的长动作（包括延续性动词的一般时和进行时）的过程中,发生了主句的短动作（瞬时性动作的一般时）,as, when, while三词都可用作连词,引出这一过程。如：As(When, While) I was walking to school, I saw Mr. Johnson.我走向学校时,见到了约翰逊先生。As (When, While)we were still laughing, the teacher came in.我们还在大笑时,老师进来了。I entered while (as, when) the meeting was going on.会议正在进行时，我进

7、来了。2.两个一般时的长动作相并进行的时候,as, when, while都可用作连词。如：He sang as(while, when) he worked.他一边干活,一边唱歌。Her voice trembled as (while, when) she spoke.她讲话时,声音发颤。3.两个进行时的长动作相并进行的时候,when, while可用作连词,as不可以。如：Mary was cooking supper while (when) her brother was playing chess.玛丽在做晚饭,那时她弟弟在下棋。Xiao Yang was singing happ

8、ily while (when) he was driving home.小杨开着车回家时,高兴地唱着歌。4.两个短动作相并进行的时候或事件同时紧接着发生时,as, when可用作连词,while不可以。如：He arrived just as (when) I stepped out of the room.就在我跨出房门时他到了。She thought of him when (just as) she caught sight of the pavilion.就在她猛地看见那亭子时,想到了他。He rose as (when) she entered.她进来时他站了起来。5.从句以系表结

9、构表示状态时,when能用作连词,while间或能用来表示“在期间”。如：When it is wet, the buses are crowded.下雨天公共汽车就拥挤。I left school when it was dark.天黑了我离开了学校。He went back to his home when he was 65.他65岁时,返回故里。6.不论从句还是主句,只要有一方用了完成时态,只有when能用作连词。如：Hardly I had finished my composition when the bell began to ring.我刚刚写完作文,铃就响了。When we

10、 got to the cinema, the film had begun.我们到电影院时,电影已经开演了。7.如果从句用瞬间性动词,主句用延续性动词,从句只能用when引出。如：When he came this morning, we were having an English lesson.今天上午他来的时候,我们在上英语课。Father was writing something when I left home.我从家出来时,父亲在写什么东西。8.在表示时间上,while不能指时间的一点,因此while所引出的从句,谓语通常用延续性动词的一般时或进行时。如：Please write while I dictate.请在我口述时,听写下来。I kept silent while he was writing.他写作时,我默不作声。9.在表示对比时,while作“然而”解,从句可用“系表结构”或延续性动词作谓语。如：He is lazy while his brother (is) diligent.他懒惰,而他弟弟勤奋。He was riding while his father walked in the dust.他在骑着马,而他父亲在尘埃中步行。10.while 还可以作“虽然”“趁着”“只要”解。如：While I like the colour of th