初中八年級英語課件If引導(dǎo)的條件狀語從句

If引導(dǎo)的條件狀語從句If

wedon'tthrowlitterintothesea,theseawon'tbepolluted.wedon'tthrowlitterintothesea從句主句if連接詞If引導(dǎo)的條件狀語從句

Theseawon'tbepollutedIf引導(dǎo)的條件狀語從句1.定義由引導(dǎo)詞if(如果)引導(dǎo)的狀語從句叫條件狀語從句。2.位置從句可放主句之前或之后，從句在前用逗號和主句隔開。例：如果我們保護環(huán)境，我們將會有一個更美麗的世界。Ifweprotecttheenvironment,

wewillhaveamorebeautifulworld.

Wewillhaveamorebeautifulworld

if

weprotecttheenvironment.If引導(dǎo)的條件狀語從句3.結(jié)構(gòu)與時態(tài)①If引導(dǎo)的條件狀語從句是一般現(xiàn)在時，主句用一般將來時。例：如果人們?yōu)榱唆~翅而殺死鯊魚，人們將會給所有的海洋生物帶來危害。If

peoplekillsharksforsharkfins,

peoplewillbringdangertoalloceanlife.

If引導(dǎo)的條件狀語從句3.結(jié)構(gòu)與時態(tài)②If引導(dǎo)的條件狀語從句是一般現(xiàn)在時，主句用情態(tài)動詞。例：如果我們用更少的紙巾，我們就能拯救更多的樹木。If

weusefewerpapernapkins,wecansavemoretrees.If引導(dǎo)的條件狀語從句3.結(jié)構(gòu)與時態(tài)③If引導(dǎo)的條件狀語從句是一般現(xiàn)在時，主句為祈使句。例：停止開車，空氣將會變得更新鮮。Stopridingincars,theairwillbecomemuchfresher.小試身手Wecanputthewastetogooduse______wesortthewaste.

A.ifB.whenC.beforeD.untilWecanputthewastetogooduse

wesortthewaste.主句從句連接詞if大顯身手2.Ifwe______somethingtostopthesaleofsharkfins,sharksmaydisappearoneday.

A.don'tdoB.doesn'tdo

C.didn’tdoD.won’tdowe______somethingtostopthesaleofsharkfins,

sharksmaydisappearoneday.

主句從句連接詞If一般將來時一般現(xiàn)在時大顯身手3.Ifwebringourownbagstogoshopping,

we______wastepollution.

A.cutdownB.don'tcutdown

C.willcutdownD.won’tcutdownwebringourownbagstogoshopping,

we______wastepollution.

主句從句連接詞If一般將來時一般現(xiàn)在時AccordingtotheEnvironmentalProtectionLaw,protectingtheenvironmentisthebasicnationalpolicyofourcountry.Andeveryonehasthedutytoprotecttheenvironment.Ifanyonebreaksthelaw,hewillbepunished.June5thistheWorldEnvironmentDay.Let'sstartwithsmallthing