Unit6NaturaldisastersPeriodFiveGrammarTeachingAims:Tousebecause,as,andsincetointroducethereasonforsomething.TeachingProcedures:Step1.Freetalk:1.Whydoyougotoschool?2.Whatwillhappentopandas,iffarmerscutdowntreesandforests?3.Whywereyoulatethismorning?4.Whatwillwedo,ifitrains?5.Whatdoyouwanttobewhenyougrowup?6.Whatdoyouusuallydoafterclass?Step2.LearngrammarAbecause,as,since均表示“因为；由于”（1）because语气最强，用来回答why，可表示已知或未知的事实。它可以和only,justy以及否定此not连用。Because引导的从句一般放在主句后面。如：IplantodoitbecauseIlikeit.________________Tomdidn’tattendthemeetingbecausehewasill.________________Youshould’tgetangryjustbecausesomepeoplearenotpolitetoyou.________________________(2)as,since语气较弱，常放在主句前。as表示的原因比较明显;since常表示对方已知的事实，相当于“既然”Asalltheseatswerefull.Hehadtostandthere.___________________Asitwassnowy,ittookmelongertogettoschool.______________________Sinceyouask,Iwilltellyou.________________________Sinceyou’renotinterested,Iwon’ttalkaboutit.___________________________Step3Exercises:Completethesentencesbyaddingtheconnectivesofreason.1.Ileftmyumbrellaatschool.Iwasinahurry.(because)2.Iwenttobedearly.Ididn’twatchtheprogramme.(as)____________________________________________________________________3.Icouldnotdomyhomework.Itwastoodifficult.(since)____________________________________________________________________4．因为我妈妈生病了，我必需要照顾她____________________________________________________________________5由于下雨,我们不上体课.7.既然你没时间,我就不说了.Homework:教后感
