前面一般上课怎么说就怎么说吧.我觉得是中秋那开场就对中秋大致介绍一下吧.

　　MooncakesaretoMid-AutumnFestivalwhatmincepiesaretoChristmas.Theseasonalroundcakestraditionallyhaveasweetfillingoflotusseedpasteorredbeanpasteandoftenhaveoneormoresaltedduckeggsinthecentertorepresentthemoon.Andthemooniswhatthiscelebrationisallabout.

　　Therearealegendwhichclaimtoexplainthetraditionofeatingmooncakes.OneTangDynastymythholdsthattheEarthoncehad10sunscirclingit.Onedayall10sunsappearedatonce,scorchingtheplanetwiththeirheat.ItwasthankstoaskillfularchernamedHouYithattheEarthwassaved.Heshotdownallbutoneofthesuns.Ashisreward,theHeavenlyQueenMothergaveHouYitheElixirofImmortality,butshewarnedhimthathemustuseitwisely.HouYiignoredheradviceand,corruptedbyfameandfortune,becameatyrannicalleader.Chang-Er,hisbeautifulwife,couldnolongerstandbyandwatchhimabusehispowersoshestolehisElixirandfledtothemoontoescapehisangrywrath.Andthusbeganthelegendofthebeautifulwomaninthemoon,theMoonFairy.

　　Ofcourse,it'sonlyalegend.

　　差不多可以开始上课.

　　不知道和你想要的开场白差多少,希望能帮到你!

　　祝讲一节完美的“中秋课”!同时也祝你中秋节快乐!