if條件句【知識要點】定義：常見的if條件狀語從句表示在某條件下， 某事很可能發生，條件是可能存在的，主句中某種情況發生的概率也是很高的。E.g.Ifyouaskhimhewillhelpyou.如果你請他幫忙，他會幫你的。E.g.Ifyoufailintheexam,youwilllethimdown.如果你考試不及格，你會讓他失望的。E.g.Ifyouhavefinishedthehomeworkyoucangohome.如果你作業做完了就可以回家了。另外，if從句還表示不可實現的條件或根本不可能存在的條件，也就是一種虛擬的條件或假設。從句多用一般過去時或過去完成時， 表示對現在或過去的一種假設。E.g.IfIwereyou,Iwouldinvitehimtotheparty.如果我是你，我會邀請他參加聚會。E.g」wouldhavearrivedmuchearlierifIhadnotbeencaughtinthetraffic要不是交通堵塞，我本會來得早一些。另外你還要注意if條件句的時態搭配if從句用一般現在時，主句用一般將來時E.g.Ifherunshellgetthereintime.如果他用跑的，他就會及時趕到那兒。E.g.Thecatwillscratchyouifyoupullhertail.如果你拉貓的尾巴，它就會抓你。if從句用一般現在時，主句用may/might/canE.g.Ifthefoggetsthickertheplanemay/mightbediverted.如果霧在大一些，飛機可能就會改在別的機場降落。E.g.Ifitstopssnowingwecangoout.如果雪停了，我們就可以出去。if從句用一般現在時，主句用must/shouldE.g.Ifyouwanttoloseweightyoumust/shouldeatlessbread.如果你想減肥，你必須少吃面包。if從句用一般現在時，主句用一般現在時E.g.Ifyouheaticeitturnstowater.也可用willturn)如果把冰加熱，它就會化成水if從句用現在進行時，主句用一般將來時E.g.IfyouarelookingforPeteryo'lfindhimupstairs.如果你是在找彼得，上樓就會找到他。if從句用現在完成時，主句用一般將來時E.g.Ifyouhavefinisheddinner'askthewaiterforthebill.如果你吃完了，我就叫服務生來算賬學習"if"引導的條件狀語從句的用法，現在總結一下：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，主句常用現在時。在if引導的條件狀語從句中，如果從句談論的是一個有可能發生的事實及其產生的相關的結果，主句用一般將來時態，從句用一般現在時態。如：E.g.Wecanwalkthereifwecan'tfindabus.E.g.Ifitrainstomorrow,wewillnotgotothezoo.E.g.Whatwillyoudoifyoufindapandaindanger.如果if條件句談論的是重復發生和預示要發生的情景和事件，則主從句大多用一般現在時態。E.g.Ifbearsareindanger,theyattackpeople.在if引導的條件狀語從句中，if和條件句位置靈活，可直接放在主句后面，若if條件句放句首， 從句后面要加逗號，和主句隔開。還要注意前后時態一致原則【經典練習】用所給詞的適當形式填空1.Ifyou (feel)tired,you (have)tohavearest.Where he (see)thefilmifhe (have)time?Ifthere (be)fewertrees,there (be)morepollution.He (dress)morecasuallyifhe (notwork)onweekends.IfMarcia (live)alone,she (keep)apetparrot.Lana (buy)anewdressiftheoldone (be)outofstyle.Thetwins (fight)ifthey (argue).8.1 (have)abakesaleifI (need)moneyforeducation.Peter (send)meabeautiful souvenir ifhe (tour)Spain.IfMrGreen (say)Iamhard-working,myparents (feel)glad.I (go)tothebeachifit (notrain)thisweek. they (have)amatchifthePE.teacher (be)busy?He (write)alettertohisgrandparentsifhe (get)hisreportcardthisweek.Ifshe (get)uplate,she (notcatch)theearlybus.Peter (major)inEnglishifhe (pass)theexamsinPekingUniversity.翻譯句子如果他到的晚了會發生什么事情？What ifhe late?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.如果我們為他組織生日聚會，大家都會來的。Everyone ifwe abirthdayparty him.如果明天不下雨，我會和你一起去公園的。Ifit tomorrow,I gotothepark you.如果她睡過頭了，就會旅游遲到的。She thetripifshe .如果他有空，他會幫助你的。Ifhe ,he ou.如果Tom考試不及格，他就沒有機會上高中了。Tom havethe togotothe highschoolifhe theexams.一般將來時專項練習一、單項選擇()1.There ameetingtomorrowafternoon.A.willbegoingtoB.willgoingtobeC.isgoingtobeD.willgotobe()2.Charlie herenextmonth.A.isn'working B.doesn'tworkingC.isntgoingtoworking D.won'work()3.He verybusythisweek,he freenextweek.A.willbe;isB.is;isC.willbe;willbeD.is;willbe()4.There adolphinshowinthezootomorrowevening.A.wasB.isgoingtohaveC.willhaveD.isgoingtobe()5. - you freetomorrow?—No.I freethedayaftertomorrow.A.Are;goingto;willB.Are;goingtobe;willC.Are;goingto;willbeD.Are;goingtobe;willbe()6.Mother meanicepresentonmynextbirthday.A.willgivesB.willgiveC.gives D.give()7.-ShallIbuyacupofteaforyou? - .(不，不要。)A.No,youwon'.B.No,youarent. C.No,pleasedo'.D.No,please.()8.-Whereisthemorningpaper? T ifforyouatonce.A.get B.amgetting C.togetD.willget()9. aconcertnextSaturday?A.TherewillbeB.WilltherebeC.TherecanbeD.Thereare()10.Iftheycome,we ameeting.A.haveB.willhave C.had D.wouldhave()11.He herabeautifulhatonhernextbirthday.A.givesB.gaveC.willgivingD.isgoingtogiving()12.He tousassoonashegetsthere.A.writesB.haswritten C.willwriteD.wrote()13.He inthreedays.A.comingbackB.camebackC.willcomebackD.isgoingtocomingback()14.Ifit tomorrow,we'llgoroller-skating.A.isn'rain B.won'rain C.doesn'rain D.doesntfine()15.-WillhisparentsgotoseetheTerraCottaWarriorstomorrow?-No, (不去).A.theywilln'. B.theywon't. C.theyaren't. D.theydon't.()16.Who we swimmingwithtomorrowafternoon?A.will;goB.do;goC.will;goingD.shall;go()17.We theworkthiswaynexttime.A.doB.willdoC.goingtodo D.willdoing()18.Tomorrowhe akiteintheopenairfirst,andthen boatinginthepark.A.willfly;willgoB.willfly;goesC.isgoingtofly;willgoesD.flies;willgo()19.Thedayaftertomorrowthey avolleyballmatch.A.willwatching B.watchesC.iswatchingD.isgoingtowatch（）20.There abirthdaypartythisSunday.A.shallbeB.willbeC.shallgoingtobeD.willgoingtobe（）21.They anEnglisheveningnextSunday.A.arehaving B.aregoingtohaveC.willhaving D.isgoingtohave（）22. you freenextSunday?A.Will;areB.Will;beC.Do;be D.Are;be（）23.He thereattentomorrowmorning.A.willB.isC.willbeD.be（）24. yourbrother amagazinefromthelibrary?A.Are;goingtoborrow B.Is;goingtoborrowC.Will;borrows D.Are;goingtoborrows（）25.-ShallIcomeagaintomorrowafternoon? - （好的）A.Yes,pleaseB.Yes,youwill.C.No,please.D.No,youwon'.（）26.It theyearofthehorsenextyear.A.isgoingtobeB.isgoingtoC.willbeD.willis（）27. openthewindow?A.WillyoupleaseB.PleasewillyouC.YoupleaseD.Doyou（）28.-Let'sgoouttoplayfootball,shallwe? -OK.I .A.willcomingB.begoingtocomeC.comeD.amcoming（）29.It usalongtimetolearnEnglishwell.A.takesB.willtakeC.spends D.willspend（）30.Thetrain at11.A.goingtoarriveB.willbearriveC.isgoingtoD.isarriving二、動詞填空。1.1 （leave）inaminut