初中八年级英语课件If引导的条件状语从句

If引导的条件状语从句If

wedon'tthrowlitterintothesea,theseawon'tbepolluted.wedon'tthrowlitterintothesea从句主句if连接词If引导的条件状语从句

Theseawon'tbepollutedIf引导的条件状语从句1.定义由引导词if(如果)引导的状语从句叫条件状语从句。2.位置从句可放主句之前或之后，从句在前用逗号和主句隔开。例：如果我们保护环境，我们将会有一个更美丽的世界。Ifweprotecttheenvironment,

wewillhaveamorebeautifulworld.

Wewillhaveamorebeautifulworld

if

weprotecttheenvironment.If引导的条件状语从句3.结构与时态①If引导的条件状语从句是一般现在时，主句用一般将来时。例：如果人们为了鱼翅而杀死鲨鱼，人们将会给所有的海洋生物带来危害。If

peoplekillsharksforsharkfins,

peoplewillbringdangertoalloceanlife.

If引导的条件状语从句3.结构与时态②If引导的条件状语从句是一般现在时，主句用情态动词。例：如果我们用更少的纸巾，我们就能拯救更多的树木。If

weusefewerpapernapkins,wecansavemoretrees.If引导的条件状语从句3.结构与时态③If引导的条件状语从句是一般现在时，主句为祈使句。例：停止开车，空气将会变得更新鲜。Stopridingincars,theairwillbecomemuchfresher.小试身手Wecanputthewastetogooduse______wesortthewaste.

A.ifB.whenC.beforeD.untilWecanputthewastetogooduse

wesortthewaste.主句从句连接词if大显身手2.Ifwe______somethingtostopthesaleofsharkfins,sharksmaydisappearoneday.

A.don'tdoB.doesn'tdo

C.didn’tdoD.won’tdowe______somethingtostopthesaleofsharkfins,

sharksmaydisappearoneday.

主句从句连接词If一般将来时一般现在时大显身手3.Ifwebringourownbagstogoshopping,

we______wastepollution.

A.cutdownB.don'tcutdown

C.willcutdownD.won’tcutdownwebringourownbagstogoshopping,

we______wastepollution.

主句从句连接词If一般将来时一般现在时AccordingtotheEnvironmentalProtectionLaw,protectingtheenvironmentisthebasicnationalpolicyofourcountry.Andeveryonehasthedutytoprotecttheenvironment.Ifanyonebreaksthelaw,hewillbepunished.June5thistheWorldEnvironmentDay.Let'sstartwithsmallthing