Unit13We’retryingtosavetheearth!SectionA(Grammarfocus—4b)【学习目标】1.学习并掌握新词汇：reusable,afford,transportation2.学习并会用以下常用表达：trytodosth.,usedtodosth.,is/aredoing,beconsidered,takepartin;playapartindoingsth.,helpwith,helpout,turnoff,insteadof,payfor,addup,affordtodosth.,not…anylonger,takeaction,It’sdifficultforsb.todosth.3.学习并掌握下列句型：1)We’retryingtosavetheearth.2)Theriverusedtobesoclean.3)Itwasconsideredthenicestriverintown.4)Theairhasbecomereallypolluted.5)Weshouldhelpsavethesharks.6)Everyoneshouldplayapartinkeepingthecityclean.7)Youcansaveelectricitybyturningoffthelightswhenyouleavearoom.8)Wecannotaffordtowaitanylongerbeforetakingaction!9)It’sdifficultforparentswithyoungchildrentousepublictransportation【重点难点】正确使用本课语法要点。【新知预习】根据句意和首字母提示完成单词。1.Itwasc________thenicestriverintown.2.Youcanalsousepaperorr_______bagsinsteadofplasticbags.3.Wecannota_______towaitanylongerbeforetakingaction!4.Wethinkthateveryoneshouldusepublict________.5.Iguesseveryoneinthiscityistryingtoimprovethee_________.【课堂探究】一、现在进行时：概念：表示现阶段或说话时正在进行的动作及行为。时间状语：now,atthistime,thesedays,etc.基本结构：am/is/are+doing否定形式：am/is/are+not+doing.一般疑问句：把be动词放于句首。二、usedto的意思是“过去经常”，其中的to是不定式符号，不是介词，所以其后接动词原形(不接动名词)。三、现在完成时：概念：过去发生或已经完成的动作对现在造成的影响或结果，或从过去已经开始持续到现在的动作或状态。时间状语：recently,lately,since…for…,inthepastfewyears,etc.基本结构：have/has+done否定形式：have/has+not+done.四、被动语态：概念：当主语为动作的承受者时，谓语要用被动语态。基本机构：“助动词be＋及物动词的过去分词”构成。含有情态动词的被动语态由“情态动词＋be＋及物动词的过去分词”构成。助动词be有人称、数和时态的变化，其变化规则与be作为连系动词时完全一样。五、情态动词should后接动词原形。（1）表示“应该，应当”Youshouldhelpyourmotherwiththehousework.你应该帮你母亲做家务。（2）表示“可能，该(=willprobably)”Heshouldarrivesoon他可能很快就到了。【达标练习】I.单项选择。()1.We’retrying______theearth.A.tosaveB.savingC.savedD.besaved()2.Mygoodfriendbecomesgoodat__________Englisheveryday.A.speakB.speakingC.speaksD.tospeak()3.I_________takedancelessons,butIdon’tanymorenow.A.usedtoB.usedC.usingD.touseto()4.Itwas________thenicestriverintown.A.consideringB.consideredC.haveconsideredD.tobeconsidered()5.Whenitcomesto________theearth,peoplemaythinkthatbigthingsshouldbedone.A.saveB.besavedC.savedD.savingII.用所给单词的适当形式填空。1.—_______youever_______(take)partinanenvironmentalproject?—Yes,Ihave.2.I’vebecomemuch_______(good)atspeakingEnglish.3.Theairhasbecomereally_______(pollute).4.Everyoneshould_______(play)apartinkeepingthecityclean.5.Iguesseveryoneinthiscityis_______(try)toimprovetheenvironment.6.Youcansaveelectricityby_______(turn)offthelightswhenyouleavearoom.7.Wecannotaffordto_______(wait)anylongerbeforetakingaction!8.I_______(help)withaClean-UpDaylastyear.III.根据所给汉语完成英语句子。1.这条河过去很干净。Theriver_____________________soclean.2.我们应该帮助拯救鲨鱼。Weshould______________thesharks.3.然而，很多人忘记了拯救地球从小事做起。However,manyforgetthatsavingtheearth______________smallthings.4.在很多商店，你不得不付塑料袋的费用Insomestores,younowhaveto______________plasticbags.5.我们认为每个人都应该使用公共交通工具。We...
