Unit 10 语法课件 2022-2023学年人教版英语八年级上册

IF引导的条件状语从句

if?Doyouknowthemeaningof......如果WhatcanyouFIND?it

willbreak.If

I

dropaglass,i

willgetwet.If

I

standinarain,I

willmiss

classes.If

I

come

toschoollate,if从句主句定义：if意为“如果”它引导的条件状语从句表示“在…条件下，某事才能发生”，在复合句中充当状语。If引导的条件状语从句位置：Ifyougototheparty,you'llhaveagreattime.You'llhaveagreattimeifyougototheparty.从句可放在主句之前或之后，但是放在主句之前须有逗号隔开If引导的条件状语从句Ifyougototheparty,you'llhaveagreattime.Iftheyhavethepartytoday,halftheclasswon'tcome.Ifweaskpeopletobringfood,they'lljustbringpotatochipsandchocolate.Wewillhaveatripifitissunnytomorrow.想一想：哪个是主句？哪个是从句？If引导的条件状语从句You'llhaveagreattime

,（主句）,ifyougototheparty(从句).Iftheyhavethepartytoday(从句）,halftheclasswon'tcome（主句）.Ifweaskpeopletobringfood(从句）,they'lljustbringpotatochipsandchocolate（主句）.Wewillhaveatrip（主句）ifitissunnytomorrow（从句）.If引导的条件状语从句具体用法如果主句是一般将来时，从句则用一般现在时。（简称：主将从现）注意事项：将来时态需注意主句一般将来时用“willdo”的形式,不使用begoingtoIfit________(rain)tomorrow,Iwillstayathome.Ifit________(notrain)tomorrow,Iwillgooutforawalk.I_________(go)withyouifyoudon'twanttogoalone.You____________(be)happyifyougototheparty.rainsdoesn’trainwillgowillbeIf引导的条件状语从句2.如果主句含有must,may,can等情态动词，从句也要用一般现在时。（简称：主情从现）

Ifyoudrivetoofast,youmayhaveanaccident.Ifyouwanttopasstheexam,you__________________(study)hard.You____________(stop)ifthetrafficlightisred.You____________(leave)ifyoufinishyourhomework.must/shouldstudymuststopcanleaveIf引导的条件状语从句3.如果主句是祈使句，从句同样要用一般现在时。（简称：主祈从现）

Don’tgoand_______(play)footballifyoudon’tfinishyourhomework.Please________(call)meifhecomesnextSunday.Ifyouneedanyhelp,please_______(let)meknow.Ifyouwanttorecord,_________(press)theredlight.playcallletpress1、if从句：一般现在时主句：一般将来时

【主将从现】2、if从句：一般现在时主句：祈使句3、if从句：一般现在时主句：含can,may,must等情态动词句子时态：If

在宾语从句中翻译为“是否”If

在条件状语从句中翻译为“如果”I’llgotoseeyouifIamfreenextweek.

Iwanttoknowifheisateacher.whether1.if在句中的含义不同注意：

if引导的条件状语从句与if引导的宾语从句的区别2.if在从句中的位置不同If引导的宾语从句放在主句之后；if引导的状语从句可放在主句之前,也可放在主句之后用”，“隔开=Ifitdoesn’train,Iwillgoouttomorrow.Iwillgoouttomorrowifitdoesn’train.Idon’tknowifthetrainhasarrived.1.Canyoutellmeifshecancometothemeeting?2.Shewillnotgothereifitisrainytomorrow.3.Ican’tguessifshewillbeangry.4.Ifwehelpeachother,webothwillgetgoodresults.

判断：if引导的条件状语从句与if引导的宾语从句宾条件宾条件3.时态要求上有区别If

引导条件状语从句的时态为一般现在时记住“主将从现”

1.Iwantedtoknowifthere

asportsmeetingnextmonth.doesn’trainwouldbe2.Ifit

,we’llholdit.If引导的宾语从句的时态由主句及本身时态决定1.if在句中的含义不同2.if在从句中的位置不同3.时态要求上有区别明白吗

if引导的条件状语从句与if引导的宾语从句的区别

if的反义词：

if...not...=unless,“如果不，除非”

Iwon’tgothereunlessIhearfromyou.(同义句)Iwon’tgothere_____I_____hearfromyou.ifdon’t

Iwon’tgotothepartyifIamnotinvited.(同义句)Iwon’tgototheparty___________Iaminvited.unlessExercises

Hewillhelpmewithmymathsifhe____free.AwasBwillbeCwouldbeDisIdon’tknow_____hewillcometomorrow.____hecomes,I’lltellyou.Aif;WhetherBwhether;WhetherCif;ThatDif;If3.Pleasetellhermytelephonenumberifshe_____(want)toknow.wantsDD8.---Wouldyoupleasetellme____next?---Thinkitover.You’llfindagoodway.AwhentodoBhowtodoCwhattodoDwheretodo9.Idon’tknowifmyuncle_____.Ifhe___,Iwillbeveryhappy.Acomes;willcomeBwillcome;willcomeCcomes;comesDwillcome;comes10.EitheryouorI_____goingtoShanghai.Onlyonepersonmaygothere.AareBwereCamDwas

CDC()11.Ifit______sunnytomorrow,I____boating.

A.isgoB.willbe,go C.is,willgoD.willbe,willgo

()12.--whatwillyoudoifit______tomorrow,

--I’llstayathomeandwatchTV.

A.rainB.rainsC.willrainD.israining

CB()13.

Ifhe______,I______himthetime. A.comes,tellB.willcome,willtell C.comes,willtellD.willcome,tell()14.Ifit______,it______cold. A.snows,willbeB.snows,is C.willsnow,willbeD.willsnow,is()15.Ifyou______astoneintowater,it______. A.put,sinksB.put,willsink C.willput,sinksD.willput,willsinkCBA1.I’msureifhe_____(go)totheparty,he________(have)agreattime.2.Iftherain_______(stop)tonight,wewillgotothecinema.3.I’llbuyacomputerifI______(have)enoughmoney.4.You_________(notget)nervousifyou_____(do)enoughexercise.6.Iwanttoknowifhe_________(come)nextweek,ifhe_______(come),I__________(t