if引導(dǎo)的條件狀語(yǔ)從句和賓語(yǔ)從句

1、If 的用法if 的 條件從句 分為真實(shí) 條件從句 和虛擬 條件從句 。真實(shí)條件從句：真實(shí)條件從句適用于主將從現(xiàn) ，是假設(shè)有可能發(fā)生的。一位置在 if 引導(dǎo)的條件狀語(yǔ)從句中，既可以放在主句之前，也可以放在主句之后。若if 條件句放句首，從句后面要加逗號(hào)，和主句隔開(kāi)。You will catch the bus if you get up early. = If you get up early, you will catch the bus.二時(shí)態(tài)1. （主祈從現(xiàn)）主句：一般現(xiàn)在時(shí)態(tài)（包含祈使句和含有情態(tài)動(dòng)詞can, may, must 等的句子）從句：一般現(xiàn)在時(shí)態(tài)2. （主將從現(xiàn)）主句：一般

2、將來(lái)時(shí)態(tài)從句：一般現(xiàn)在時(shí)態(tài)3. 從句 : 現(xiàn)在進(jìn)行時(shí)，主句 : 一般將來(lái)時(shí)If you are looking for Peter you ll find him upstairs. 如果你是在 找彼得，上樓就會(huì)找到他。4 if 從句用現(xiàn)在完成時(shí)，主句用一般將來(lái)時(shí)If you have finished dinner I ll ask the waiter for the bill. 如果你吃完了，我就叫服務(wù)生來(lái)算賬5.if 條件句談?wù)摰氖侵貜?fù)發(fā)生和預(yù)示要發(fā)生的情景和事件，則主從句大多用一般現(xiàn)在時(shí)態(tài)。如： If bears are in danger ,they attack people.

3、三注意事項(xiàng)1 . 在 if 引導(dǎo)的條件狀語(yǔ)從句中，當(dāng)主句是一般將來(lái)時(shí)態(tài)時(shí)，不能使用 be going to 結(jié)構(gòu)， 而要用 will.2 .在if引導(dǎo)的條件狀語(yǔ)從句中,不能使用some,而要用any. 四同義句轉(zhuǎn)化1. 借助于祈使句+and / or+簡(jiǎn)單句轉(zhuǎn)化，and表示順承，or表示轉(zhuǎn)折。例如： （1）If you work hard, you ll pass the exam.Work hard, and you ll pass the exam.（2）If you do n t hurry up, you ll be late.Hurry up, or you ll be late.2

4、. 借助于介詞with 或者 without 來(lái)轉(zhuǎn)換例如： If you help me, I ll finish my job soon.With your help , I ll finish my job soon.if 條件句不一般 , 幾個(gè)要點(diǎn)記心間條件句 , 放在前 , 逗號(hào)要放句中間。條件句表可能，主句 多用將來(lái)時(shí)；條件句表事實(shí)，主句常用現(xiàn)在時(shí)。虛擬 條件從句 : 虛擬條件從句是假設(shè)不太可能發(fā)生的。IF 的 虛擬語(yǔ)氣 有三種：內(nèi)容從句 主句與現(xiàn)在事實(shí)相反動(dòng)詞過(guò)去式（ be 用 were ） would/could/should/might+ 動(dòng)原與將來(lái)事實(shí)相反should/wer

5、e to+ 動(dòng)原 would/could/should/might+ 動(dòng)原與過(guò)去事實(shí)相反had+ 過(guò)分would/could/should/might+ have+過(guò)分下面三句依次是上面三種情況的例句：If I were you ,I would/could/should/might do that.If I had know that yesterday , I would/could/should/might have told you .If it should rain , the crops would/could/might be saved.If 引導(dǎo)的賓語(yǔ)從句一 if 引導(dǎo)賓語(yǔ)

6、從句時(shí)，意思為：是否，從句的時(shí)態(tài)通常要和主句保持一致。【例句】 I want to know if he lives there.我想知道他是否住在那兒。 He asked meif I could help him. 他問(wèn)我是否能幫他?！究疾辄c(diǎn)】 if 、 whether 引導(dǎo)的賓語(yǔ)從句的區(qū)別 1. if 或 whether 引導(dǎo)賓語(yǔ)從句時(shí)， 作“是 否”講，常放在動(dòng)詞 ask、see、say、know和find out 等后面。一般情況下，兩者?？蓳Q 用，在口語(yǔ)中多用 if ?！纠洹?Nobody knows whether / if it will rain tomorrow.沒(méi)有人知

7、道明天是否下雨。 Lucy asked whether / if they had a cotton sweater.露西問(wèn)他們是否有棉制的毛衣。二 . 注意事項(xiàng)： if 或 whether 引導(dǎo)賓語(yǔ)從句時(shí)，要注意三個(gè)方面，即連詞、語(yǔ)序和時(shí)態(tài)。1. if 或 whether 既不能和 that 或其他連詞(副詞)同時(shí)使用，也不能省略?！纠洹?我不知道他今天是否會(huì)來(lái)。 誤 I don t know that if(whether) he will come here today. 正 I don t know if(whether) he will come here today.他走過(guò)來(lái)看看

8、貓是否出了毛病。 誤 He came to see what if (whether) there was anything wrong with his cat . 正 He came to see if (whether) there was anything wrong with his cat .2.if 或 whether 引導(dǎo)賓語(yǔ)從句時(shí)，雖具有疑問(wèn)的意義，但其從句應(yīng)用陳述句的語(yǔ)序?！纠洹?Did you know the way to the hospital? The old woman asked me.The old woman asked me if / whether

9、I knew the way to the hospital.老婦人問(wèn)我是否知道去醫(yī)院的路。3. if 或 whether 引導(dǎo)的賓語(yǔ)從句應(yīng)和主句的時(shí)態(tài)保持一致。即主句為一般現(xiàn)在時(shí)，從句用任一種時(shí)態(tài)；主句為一般過(guò)去時(shí)，從句則用過(guò)去時(shí)中的任一種時(shí)態(tài)。【例句】 I don t know if (whether) he has come here. 我不知道他是否來(lái)過(guò)這兒。Tom asked if (whether) I had read the book.湯姆問(wèn)我是否看過(guò)這本書(shū)。三 If 和 whether 兩者不能互換的情況1 . 只能用 whether 的情況 在動(dòng)詞不定式之前只能用 whet

10、her ：【例句】 I can t decide whether to stay.我不能決定是否留下。2 .在whetheror not的固定搭配中：【例句】 I want to know whether it s good news or not. 我想知道它是不是好消息。3. 在介詞后，只能用 whether ：【例句】 His father is worried about whether he loses his work.他的父親擔(dān)心他是否會(huì)失去工作。4. 用 if 會(huì)引起歧義時(shí)：【例句】 Could you tell me if you know the answer?這句話有兩種

11、意思： “你能告訴我你是否知道答案嗎？”或“如果你知道答案，請(qǐng)告訴我，好嗎？” 。 如用 whether則可避免歧義?！究碱}鏈接】 I don t know they could pass the exam or not.A. why B. if C. that D. whether答案：D 解題思路：本題考查if與whether的區(qū)別，在 whetheror not的固定搭配中通 常只用 whether 。 練習(xí)解：句型轉(zhuǎn)換1. Do they want fried chicken? He asked the boys.(改為賓語(yǔ)從句 )He asked the boys they frie

12、d chicken.2. Was the watch made in Shanghai? I don t know.( 改為賓語(yǔ)從句 )I don t know the watch made in Shanghai.3. “ Do you want to try something new? ” Tom s mother asked him.( 同義句轉(zhuǎn)換)Tom s mother asked him to try something new.答案： 1. if / whether, wanted 2. if / whether, was 3. if / whether he wanted 一

13、、用所給詞的適當(dāng)形式填空1.If you (feel) tired, you (have) to have a rest.4. If there (be) fewer trees, there ( be) more pollution.5. If Marcia (live) alone, she ( keep)a pet parrot.6. Lana ( buy) a new dress if the old one _(be) out of style.9. Peter ( send) me a beautiful souvenir if he (tour) Spain.10. If Mr

14、Green (say) I am hard- working, my parents ( feel) glad.11. I(go) to the beach if it ( not rain)this week.13. He (write) a letter to his grandparents if he (get) his report card this week.14. If she (get) up late, she ( not catch)the early bus.15. Peter (major) in English if he (pass) the exams in P

15、ekingUniversity.16. 如果努力學(xué)習(xí)，你就會(huì)取得好成績(jī)。If you , you good .17. 他如果看電視太久了，他的父母會(huì)不高興。If he TV too much, his parents unhappy. 18. 如果我們?yōu)樗M織生日聚會(huì)，大家都會(huì)來(lái)的。Everyoneif wea birthday party him.19. 如果明天不下雨，我會(huì)和你一起去公園的。If it tomorrow, Igo totheparkyou.21.如果他有空，他會(huì)幫助你的。Ifheheyou.23.你如果抄同學(xué)的作業(yè)就不能學(xué)好各門(mén)功課。Youer students good

16、at homework.allthesubjectsifyoutheoth1.If you _ to the party,you ll have agreattime.A. will go B. wentC.2. It will be a long timegoD. going Peter hiswork.A. since, ishD.3. What willhas finishedbefore, finishes.father usB. after, finishesfrom Japan?C. when,A. take4. WeifangB. bringC.is famous carryD.

17、 makekites.A. forB. toC. on5 I her the answer ifD. withshe me.A. can tell, askD.6.- Whatwill askB.will tell,asksare you going towill tell,willdo tomorrow?askC. wouldI單項(xiàng)選擇（willWellthelibrary.tell,go totomorrow if itfinA.isnrain B.rainC.wontrain D.doesn train7. Do-Sorry,you Iknow dontwhenhewillcome ba

18、ck tomorrow?know.Whenheback, I lltellyou.D. may comeA. comes B. will come C. come8. What will you do if you _ tothe oldfolk shome visit?A. goB. wentC. goingD.will go9. If I eat food, I ll be veryfat.A. too manyB. many tooC. too muchD.much too10. I ll give the book to himif he_ herenextSunday.A. will comeB. comesC. iscomingD.came11. There an English film inourschool tomorrow.A. is going to haveB. willhaveC. isgoingto beDhas12. Could you tell us where ？A. will the next Olympic Games heldB. the next Olympic Games will be heldC. would the next Olympic Games be heldD. the next Olympic Games