人教版必修4Unit2 Using language Reading 課件

Unit2Usinglanguage

ReadingChemicalororganicfarming?Wordspreview

chemicalproductionbacteriapestnutritionmineral

adj.化學(xué)的；關(guān)于化學(xué)的n.生產(chǎn)；制造n.細(xì)菌n.害蟲；害獸；害鳥n.營養(yǎng)；滋養(yǎng)；食物n.礦物；礦石

discoveryfocussoilreduceroot

n.發(fā)現(xiàn)；發(fā)覺n.焦點(diǎn)；中心點(diǎn)vt.集中；聚焦n.土壤vt.減少；減縮n.根；根源Wordspreview

skimunderlinesummarycomment

vt.瀏覽；略讀vt.畫底線標(biāo)出；強(qiáng)調(diào)n.總結(jié)；摘要；概要n.評論；議論vi.&vt.表達(dá)意見;

做出評論Wordspreview

Expressionspreview

buildupleadtofocusonkeep…freefrom/of逐漸增強(qiáng);建立;開發(fā)導(dǎo)致;造成(后果)集中(注意力，精力等)于使…免受(影響，傷害等)；使…不含(有害物)

OrganicFarmingWhataregenetically-modifiedfoods?

ThetermGMfoodsorGMOs(genetically-modifiedorganisms)ismostcommonlyusedtorefertocropplantscreatedforhumanoranimalconsumptionusingthelatestmolecularbiologytechniques.WhataresomeoftheadvantagesofGMfoods?Theworldpopulationhastopped6billionpeopleandispredictedtodoubleinthenext50years.Ensuringanadequatefoodsupplyforthisboomingpopulationisgoingtobeamajorchallengeintheyearstocome.GMfoodspromisetomeetthisneedinanumberofways:Firstreading(3ms)Readthepassageonpage14,thenfindoutthemainideaofeachparagraph.Para1:Para2:Para3:Para4:Long-termuseoffertilizerscancausedamagetothelandandpeople‘shealth.Theproblemcausedbychemicalfertilizers.Somefarmersandmanycustomersarebeginningtoturntoorganicfarming.Organicfarmersalsousemanyothermethodstokeepthesoilfertile.Secondreading(5ms)Readthetextagainandanswerthefollowingquestions:1Whyarechemicalfertilizerssopopularinfarmingtoday?2Whatproblemscanbecausedbyusingchemicalfertilizers?3Whatisorganicfarming?4Whatisthemainreasonforusingorganicfarmingmethods?1.Whyarechemicalfertilizerssopopularinfarmingtoday?Theycanstopcropdiseaseandincreaseproduction.2Whatproblemscanbecausedbychemicalfertilizers?Therearethreeproblems.First,chemicalfertilizersaffectthesoilandthewatersupplybadly.Second,theyallowfarmerstogrowthesamecropyearafteryearandexhaustthesoil.Third,theykillbothhelpfulandharmfulpests.Organicfarmingissimplyfarmingwithoutusinganychemicals.3Whatisorganicfarming?4.Whatisthemainreasonforusingorganicfarmingmethods?Ahealthysoilreducesdiseaseandhelpscropsgrowstrongandhealthy.Thirdreading(8ms)Readthetextagain,andfillinthefollowingforms.MethodsoforganicfarmingAdvantagesofmethods1Farmersusenaturalwastefromanimals.1Thismakesthesoilricherinmineralsandsomorefertile.2Farmersoftenchangethekindofcropineachfieldeveryfewyears.2Changingthecropsrenewsthemineralsinthesoilandhelpsitbecomerichandhealthy.MethodsoforganicfarmingAdvantagesofmethods3Farmersplantcropswithdifferentlengthsofroots.3Thisusesdifferentlevelsofsoil.4Farmerssometimesplantgrassbetweencropsandleaveitintheground.4Thispreventswindorwaterfromcarryingawaysoilandactsasanaturalfertilizer.Whatisthedisadvantageofusingchemicalfertilizers?1.Leavingchemicalsinthegroundforalongtimeisnotgoodforthesoilorthewatersupply.2.Farmeroftengrowthesamecropyearafter.Asaresult,thesoilgetsexhausted.3.Chemicalfertilizerskillbothhelpfulandharmfulbacteriaandpests.Retelling(8ms)Retellthetextaccordingtothechart:OrganicfarmingI.Cropsgrowingwithnaturalfertilizers.II.Farmersprefernaturalwastefromanimals.NaturalfertilizerChemicalfertilizer1.make…richerandmorefertile2.reduce…andhelp…strong3.thefertilizerskill…andhealthy4.keepfree…fromchemicals1.leaving…isnotgood2.grow…yearafteryearIII.Farmerschangecropseverytwoorthreeyears.…tomakesurewhatisleft…Languagepoints1Thesechemicalsinthefoodsupply

buildupinpeople’sbodiesovertime.buildup

增強(qiáng);建立；開發(fā)Hardworkingconditionsbuildupcharacter.艱苦的工作條件能磨練人的性格。

2Manyofthesechemicalscanleadtocancerorotherillnesses.leadto:導(dǎo)致；造成Toomuchworkandtoolittlerestoftenleadtoillness.

過量的工作和過少的休息會(huì)引起疾病。AllroadsleadtoRome.

條條大道通羅馬。3Theyfocusonkeepingtheirsoilrichandfreeofdisease.focuson:集中(注意力，精力等）于Youshouldfocusyourattentiononyourwork.

把注意力集中在你的工作上。

Olympus:Focusonlife.

奧林巴斯：瞄準(zhǔn)生活。4Thisalsokeepstheair,soil,waterandcropsfreefromchemicals.keeps…freefrom/of:使…免受（影響，傷害登）；使不含（有害物）keepfrom:

阻止;妨礙

Ihopeyouwillkeepfromdoinganythingrash.

我希望你不要做出任何魯莽的事情來。

5Recently,however,scientistshavebeenfindingthatlong-termuseofthesefertilizerscancausedamagetothelandand,evenmoredangerous,topeople’shealth然而最近,科學(xué)家們發(fā)現(xiàn)長期使用化肥會(huì)給土地造成損害,甚至更危險(xiǎn)的是會(huì)給人類的健康造成損害.1(1)however為副詞,意為”然而，可是”，表轉(zhuǎn)折，可用于句首,句末,句中,如在句中,起前后都要加逗號.例如:He,however,couldn’tpayfortheeducationthatyoungAlbertneeded.然而,他無法支付小艾伯特的教育費(fèi)用(2)however為連詞,引導(dǎo)讓步狀語從句,相當(dāng)于nomatterhow,修飾形容詞或副詞.例如:Howeverhotitis,hewillnevertakeoffhiscoat.=Nomatterhowhotitis,hewillnevertakeoffhiscoat.無論多么熱,他都不會(huì)把外套脫掉.Howeverfastyourun,youcan’tcatchupwitha