if引導的條件狀語從句和賓語從句

If的用法if的條件從句分為真實條件從句和虛擬條件從句。真實條件從句：真實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引導的條件狀語從句中，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，和主句隔開。Youwillcatchthebusifyougetupearly.=Ifyougetupearly,youwillcatchthebus.二．時態(tài)（主祈從現(xiàn)）主句：一般現(xiàn)在時態(tài)（包含祈使句和含有情態(tài)動詞 can,may,must等的句子）從句：一般現(xiàn)在時態(tài)（主將從現(xiàn)）主句：一般將來時態(tài)從句：一般現(xiàn)在時態(tài)從句:現(xiàn)在進行時，主句:一般將來時IfyouarelookingforPeteryou’llfindhimupstairs.如果你是在找彼得，上樓就會找到他。．if從句用現(xiàn)在完成時，主句用一般將來時IfyouhavefinisheddinnerI’llaskthewaiterforthebill.如果你吃完了，我就叫服務(wù)生來算賬條件句談?wù)摰氖侵貜桶l(fā)生和預示要發(fā)生的情景和事件，則主從句大多用一般現(xiàn)在時態(tài)。如：Ifbearsareindanger,theyattackpeople.三．注意事項在if引導的條件狀語從句中，當主句是一般將來時態(tài)時，不能使用begoingto結(jié)構(gòu)，而要用will.在if引導的條件狀語從句中 ,不能使用some,而要用any.四．同義句轉(zhuǎn)化借助于祈使句+and/or+簡單句轉(zhuǎn)化，and表示順承，or表示轉(zhuǎn)折。例如：（1）Ifyouworkhard,you’llpasstheexam.Workhard,andyou’llpasstheexam.（2）Ifyoudon’thurryup,you’llbelate.Hurryup,oryou ’llbelate.借助于介詞 with或者without來轉(zhuǎn)換例如：Ifyouhelpme,I’llfinishmyjobsoon.Withyourhelp,I ’llfinishmyjobsoon.if條件句不一般,幾個要點記心間條件句,放在前,逗號要放句中間。條件句表可能，主句多用將來時；條件句表事實，主句常用現(xiàn)在時。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的虛擬語氣有三種：內(nèi)容 從句主句與現(xiàn)在事實相反 動詞過去式（be用were）would/could/should/might+動原與將來事實相反 should/wereto+動原would/could/should/might+動原與過去事實相反 had+過分 would/could/should/might+have+ 過分下面三句依次是上面三種情況的例句：IfIwereyou,Iwould/could/should/mightdothat.IfIhadknowthatyesterday,Iwould/could/should/mighthavetoldyou.Ifitshouldrain,thecropswould/could/mightbesaved.If引導的賓語從句一．if引導賓語從句時，意思為：是否，從句的時態(tài)通常要和主句保持一致?！纠洹縄wanttoknowifhelivesthere. 我想知道他是否住在那兒。HeaskedmeifIcouldhelphim.他問我是否能幫他?！究疾辄c】if、whether引導的賓語從句的區(qū)別1.if或whether引導賓語從句時，作“是否”講，常放在動詞ask、see、say、know和findout等后面。一般情況下，兩者?？蓳Q用，在口語中多用if。【例句】Nobodyknowswhether/ifitwillraintomorrow. 沒有人知道明天是否下雨。Lucyaskedwhether/iftheyhadacottonsweater. 露西問他們是否有棉制的毛衣。二.注意事項：if或whether引導賓語從句時，要注意三個方面，即連詞、語序和時態(tài)。if或whether既不能和that或其他連詞(副詞)同時使用，也不能省略?！纠洹课也恢浪裉焓欠駮?。[誤]Idon’tknowthatif(whether)hewillcomeheretoday.[正]Idon’tknowif(whether)hewillcomeheretoday. 他走過來看看貓是否出了毛病。[誤]Hecametoseewhatif(whether)therewasanythingwrongwithhiscat.[正]Hecametoseeif(whether)therewasanythingwrongwithhiscat.或whether引導賓語從句時，雖具有疑問的意義，但其從句應(yīng)用陳述句的語序?！纠洹緿idyouknowthewaytothehospitalTheoldwomanaskedme.Theoldwomanaskedmeif/whetherIknewthewaytothehospital. 老婦人問我是否知道去醫(yī)院的路。if或whether引導的賓語從句應(yīng)和主句的時態(tài)保持一致。即主句為一般現(xiàn)在時，從句用任一種時態(tài)；主句為一般過去時，從句則用過去時中的任一種時態(tài)?！纠洹縄don’tknowif(whether)hehascomehere.我不知道他是否來過這兒。Tomaskedif(whether)Ihadreadthebook. 湯姆問我是否看過這本書。三．If和whether兩者不能互換的情況只能用whether的情況在動詞不定式之前只能用whether：【例句】Ican’tdecidewhethertostay. 我不能決定是否留下。在whether…ornot的固定搭配中：【例句】Iwanttoknowwhetherit ’sgoodnewsornot.我想知道它是不是好消息。在介詞后，只能用whether：【例句】Hisfatherisworriedaboutwhetherheloseshiswork.他的父親擔心他是否會失去工作。用if會引起歧義時：【例句】Couldyoutellmeifyouknowtheanswer 這句話有兩種意思：“你能告訴我你是否知道答案嗎”或“如果你知道答案，請告訴我，好嗎”。如用whether則可避免歧義?！究碱}鏈接】Idon’tknow theycouldpasstheexamornot.A.whyB.ifC.thatD.whether答案：D解題思路：本題考查if與whether的區(qū)別，在whether…ornot的固定搭配中通常只用whether。練習解：句型轉(zhuǎn)換 1.DotheywantfriedchickenHeaskedtheboys.(改為賓語從句)Heaskedtheboys they friedchicken.WasthewatchmadeinShanghaiIdon’tknow.(改為賓語從句 )Idon’tknow thewatch madeinShanghai.“Doyouwanttotrysomethingnew”Tom’smotheraskedhim.(同義句轉(zhuǎn)換)Tom’smotheraskedhim totrysomethingnew.答案：1.if/whether,wanted2.if/whether,was3.if/whetherhewanted一、用所給詞的適當形式填空you (feel)tired,you (have)tohavearest.Ifthere (be)fewertrees,there (be)morepollution.IfMarcia (live)alone,she (keep)apetparrot.Lana (buy)anewdressiftheoldone __(be) outofstyle.Peter (send)meabeautifulsouvenirifhe (tour)Spain.IfMrGreen (say)Iamhard-working,myparents (feel)glad. _(go)tothebeachifit (notrain)thisweek. (write)alettertohisgrandparentsifhe____(get)hisreportcardthisIfshetheearlyPeter_week. bus. (get)_(major)inuplate,she___Englishifhe____(pass)__(thenotcatch)examsinP

ekingUniversity.如果努力學習，你就會取得好成績。Ifyou ,you good .他如果看電視太久了，他的父母會不高興。Ifhe TVtoomuch,hisparents unhappy.18.如果我們?yōu)樗M織生日聚會，大家都會來的。Everyone ifwe abirthdayparty him.19.如果明天不下雨，我會和你一起去公園的。Ifit tomorrow,I gotothepark you.21.如果他有空，他會幫助你的。Ifhe ,he you.23.你如果抄同學的作業(yè)就不能學好各門功課。You goodatallthesubjectsifyou theotherstudents’homework.I單項選擇（youA.totheparty,B.wentyou’llhaveagreat

goingtime.2.Itwillbealongtime Peter hiswork.A.ish3.since,D.WhatwillhasfinishedyouA.totheparty,B.wentyou’llhaveagreat

goingtime.2.Itwillbealongtime Peter hiswork.A.ish3.since,D.Whatwillhasfinishedbefore,finishes.father usB.after,finishesfromJapanC.A.4.A.5．Itake B.bring C.Weifangisfamous for B.to C.on hertheanswerifcarrykites.D.sheD.makewith me.A.ask6.cantell,D.-Whatwillaskwilltell, asksareyougoingB.towilldotell, willtomorrowaskCC.willD.gogoWe’llthelibrarywouldtell,gotowhen,willtomorrowifitfinA.isn’trainB.rainC.won’t rainD. doesnA.isn’trainB.rain7.—Doyouknowwhenhewillcomebacktomorrow--Sorry, Idon’t know.Whenhe____back,I’lltellyou.

8.Whatwillyoudoifyou totheoldfolk’shomevisitA.9.A.go B.went C.going D.willgoIfIeat food,I’llbeveryfat.toomany B.manytoo C.toomuch D.muchtoo10.I’llgivethebooktohimifhe___herenextSunday.A.willcome B.comes C.iscoming D.came11.A.There anEngli