Unit2SavingtheEarthTopic2Pollutionhascausedtoomanyproblems.SectionALanguagegoalsRevision：一般過去時(shí)和現(xiàn)在完成時(shí)的用法區(qū)別一般過去時(shí)現(xiàn)在完成時(shí)用法連用的詞和短語表示過去發(fā)生或已完成的動(dòng)作對現(xiàn)在的影響或產(chǎn)生的結(jié)果（與現(xiàn)在無關(guān)）表示過去發(fā)生的動(dòng)作或存在的狀態(tài)（與現(xiàn)在無關(guān)）yesterday,last+時(shí)間名詞,時(shí)間段+ago,in2005,inthepast,justnow…

for+時(shí)間段,since,recently,sofar,already,yet,just,ever,never,beforeinthepast+時(shí)間段,()()()()()()415362washtheearthawaymanytreeschangeintodesertforestsgonecutdowntrees1.Theboyandgirlsaretalkingabout___________.differenttypesofsandstormsthereasonsforsandstormssandstormsindifferentcities2.What’stheweatherliketoday?

3.Whatcausesthesesandstorms?

4.Dowestillneedtodosomethingtoprotecttheenvironment?

1bListento1aandchoosethebestanswer.BIt’sbad.Thewindissostrong.Andthesandreallyhurtsface.Peoplehavecutdowntoomanytrees.Asaresult,alotofrichlandhaschangedintodesert.Yes,wedo.Althoughwehavebuilt“TheGreenGreatWall”,westillneedtodosomethingtoprotecttheenvironment.Tree’sfunctions

A.Treescanstopthewindfromblowingtheearthaway.B.lotofwatercanbesavedbyforests.C.Theycanalsostopthewaterfromwashingtheearthaway.Keypoints

1.when表示“當(dāng)......時(shí)候”+延續(xù)性v./短暫性v.while表示“當(dāng)......時(shí)候”只能+延續(xù)性v.eg.1.When/WhieMargowastalkingonthephone,hersisterwalkedin.2.CindywaswearingapinkshirtwhenIsawhim.▲while“然而”，表對比;“一邊---，一邊---”，表示兩個(gè)動(dòng)作同時(shí)發(fā)生。2.change...into=turn...into把......變成......3.stopsb.(from)doingsth.阻止某人做某事=preventsb.(from)doingsth.=keepsb.fromdoingsth.▲keepsb.doingsth.讓某人一直做某事4.cutdown“砍倒”代詞放中間5.anumberof“許多”(修飾主語，謂語當(dāng)做復(fù)數(shù)）thenumberof“......的數(shù)量”(作主語，謂語用單數(shù)）Keypoints

▲

用what’s來提問，用large/small來修飾。eg.1.Anumberofstudents__________(have)thesameproblem.2.Thenumberofthestudentsinourschool______(be)over3,000.6.blow…away吹走wash…away沖走eg.1.Thewindwillblowtheearthaway.2.Alotofwaterwillwashtheearthaway.7.although引導(dǎo)讓步狀語從句，意為“盡管，即使”，可換為though/eventhough,其后句中不能出現(xiàn)but。eg.Althoughthereweresandstormsbefore,nowwehavebuilt“TheGreenGreatWall"8.V-ing作主語，謂語動(dòng)詞用單數(shù)eg.Cuttingdowntreesaffectstheweathersomuch.9.beharmfulto=doharmto對...有害10.beindanger(of)處于(…的)危險(xiǎn)中haveisKeypointsUsesomeone,something,anything,somewhere,anywheretofillintheblanks.somethingsomeone

anythingsomewhereanywhereasaresult,changeinto,dosomething,stop…from,blow…away

haschangedintoblowsawaydosomethingstopfromAsaresult2.Completethesentenceswiththecorrectformsofthegivenphrasesinthebox.

4.A.Listentothepassageandcirclethephrasesyouhear.

B.Listenagainandfillintheblanks.doourbest

indangerofplentyoffewerandfewer1.剛才2.變成/轉(zhuǎn)換成3.阻止某人做某事4.對......有影響5.把......沖掉/洗掉(吹走，帶走）6.許多（謂語v.用復(fù)數(shù)）7.......的數(shù)量（謂語v.用單數(shù)）11.對...有害12.開始存在，產(chǎn)生13.處于(…的)危險(xiǎn)中15.足夠的，大量的ExercisesinclassExercisesinclassBCABDBDBDSummaryWelearn:1.Somewords:sand,although

2.Somephrases:changeinto,humanbeing

3.Somesentences:

(1)Asaresult,alotofrichlandhaschanged

intodesert.

(2)Treescanstopthewindfromblowingtheearthaway.

Wecan:1.Usetheindefinitepronounandadverb.

2.Talkaboutthesandstormanditsharm.