第七--when-while-as-區(qū)別及練習.

1、Whenwhileas 區(qū)別一、根據(jù)從句動作的持續(xù)性來區(qū)分1、“主短從長”型：即主句是一個短暫性動作，而從句是一個持續(xù)性動作，此時三者都可用。如：Jim hurt his arm while when， as he was playing tennis. 吉姆打網(wǎng)球時把手臂扭傷了。2、“主長從長” 型：即主句和從句為兩個同時進行的動作或存在的狀態(tài)，狀態(tài)延續(xù)到從句所指的整個時間，此時通常要用while 。且強調(diào)主句動作或I always listen to the radio while I m driving.我總是一邊開車一邊聽收音機。He didn t ask me in; he kept

2、 me standing at the door while he read the message. 他沒有讓我進去，他只顧看那張條子，讓我站在門口等著。但是， 若主句和從句所表示的兩個同時進行的動作含有“一邊, 一邊”之意時，則習慣上要用 as。如 ：He swung his arms as he walked.他走路時擺動著手臂。3、“主長從短”型：即主句是一個持續(xù)性動作，而從句是一個短暫性動作，此時可以用as或 when，但不能用 while 。如：It was raining hard when as we arrived.我們到達時正下著大雨。二、根據(jù)主句與從句動作是否同時發(fā)生來區(qū)

3、分1、若主句與從句表示的是兩個同時發(fā)生的短暫性動作，含有類似漢語“一英語一般要用 as (也可用 when)。如：, 就的”意思，The ice cracked as when I stepped onto it.我一踩冰就裂了。2、若主句與從句表示的是兩個幾乎同時發(fā)生的短暫性動作，含有類似漢語“剛要“正要 , 卻”的意思，英語一般要用 as(也可用 when)，且此時通常連用副詞,just。如：就”I caught him just when as he was leaving the building. 他正要離開大樓的時候，我把他截住了。三、根據(jù)是否具有伴隨變化來區(qū)分若要表示主句動作伴隨

4、從句動作同時發(fā)展變化，有類似漢語“隨著”的意思，英語習慣上要用 as，而不用 when 或 while 。如：The room grew colder as the fire burnt down.隨著爐火逐漸減弱，房間越來越冷。注：若不是引導從句，而是引出一個短語，則用with ，不用 as。如 ：With winter coming on, it s time to buy warm clothes. 隨著冬天到來，該買暖和衣裳了。四、根據(jù)從句動作的規(guī)律性來區(qū)分若暗示一種規(guī)律性，表示“每當,的時候”，英語一般要用when 。 如 ：Its cold when it snows.下雪時天冷。

5、五、根據(jù)主從句動作的先后順序來區(qū)分若主句與從句所表示的動作不是同時發(fā)生，而是有先后順序時，一般要用when 。如： When he arrives hell tell us all about the match. 等他到了，他會好好給我們講講那場比賽的情況。六、根據(jù)是否具有“趁機”意味來區(qū)分1、若從句所表示的“當,的時候”具有“趁機”的意味，則通常用while。如：Strike while the iron is hot.趁熱打鐵。七、根據(jù)是否用作并列連詞來區(qū)分when 可用作并列連詞，表示“這時 (突然 )”； while 也可以用作并列連詞，表示“而” “卻” (表示對比 )；但 as

6、則沒有類似用法。如：I was just about to go to bed when I heard a knock on the door. 我正要睡覺，聽見有人敲門。 One person may like to spend his vacation at the seashore, while another may prefer the mountain s.八、根據(jù)所引出的省略句來區(qū)分1 、如：as 和when 之后均可直接跟一個名詞，構成省略句；但是As When a boy, he lived in Japan. 他小時候在日本。while一般不這樣用。2、when 和 wh

7、ile 之后可接現(xiàn)在分詞、介詞短語、 形容詞等構成省略句，但 as 一般不這樣用。如：When While reading, he fell asleep.他看書時睡著了。一用所給動詞正確行使填空1. I _ (have) my breakfast at half past six yesterday morning.2. Mary _ (go) over her lessons from six to seven last night. John and peter _(do) the same thing.3. What _ you _ (do) at that time? We _ (w

8、atch) TV.4. Was your father at home yesterday evening? Yes ,he was. He _ (listen) to the radio.5. They _(not make) a model ship when I saw him.6. _ they _ (have) a meeting at 4 yesterday afternoon?7. _ it _(rain) when you left school? Yes, it _. (No, it _)8. What _ your father _ (do) when he was you

9、r age?9. One day, Edison _ (wait) for a train to arrive, and suddenly a little boy ran to the track(軌道) to play.10. He asked me if I _ (go) fishing that afternoon.11. The three of them were in a hurry because their plane _ (leave) in five minutes.12. In a letter, john told us that he _ (come) to chi

10、na next month.13. When the bell rang, jenny _ (wait) in her seat.14. She _ (make) her dress the whole afternoon.15. While my father _(look) through the evening paper, he suddenly _ a cry.16. When I _ (come) in the room, he _ (see) me, for he _ (read) something17. When we _ (arrive) at the village, i

11、t _ (get) dark and it _ (rain) hard.18. I _ (know) you _(wait) for me here.19.One day a little monkey _ (play) in a tall tree. A mother crocodile(鱷魚 ) _ (look) forfood near the bank.20.What _ your father _ (do) yesterday evening? He _(study) at the evening school.21.Later his parents found that he _

12、 (sit) on some eggs.22.When he knocked at the door, my aunt _ (cook)23.The students _ (sing) and _ (dance) happily on the playground at that time.24.I _ (write) a letter when the door bell rang.25.We had no classed at that time. We _ (plant) trees.二 .改錯1.She is fat but I am thin.2.It was raining whi

13、le we arrived.3.She sang while he walked.三.選擇最佳答案：1.She thought I was praising her child ，_， in fact ，I was scolding him for his bad behaviors at school.A.what B.whileC.so thatD.therefore2.I do every single bit of housework _ my husband Bob just does the dishes now and then.A.whileB.sinceC.whenD.as3

14、.We were swimming in the lake _ suddenly the storm started.A.whenB.whileC.untilD.befor四填空： whenwhile1._ Margo was talking on the phone,her sister walked in.2._ we visited the school,the children were playing games.3._ Sarah was at the barbers,I was going to class.4._ I saw Carlos,he was wearing a gr

15、een shirt.5._ Allen was cleaning his room,the phone rang.6._ Rita bought her new dog,it was wearing a little coat.7.He was driving along _ suddenly a woman appeared.8. _ Jake was waiting at the door, an old woman called to him. 9.He was reading a book _suddenly the telephone rang.10. _ it began to rain, they were playing chess.11. She saw a taxi coming _ the woman was waiting under