英语：必修4 Unit2 Working the land--Listening&Writing课件

Unit2WorkingthelandListeningandwritingListeningonpage48Whatmakestheworld’sdesertgrow?Firsttickthecausesyouthinkaretrue.Thenlistentothetapeandtickwhatyouhear.1Heatandlittlerain.2Turingforestsintofarmland.3Overusingfieldstofeedfarmanimals.YouthinkYouhear4Usingnewscientificfarmingmethods.5Wastingwaterinfarmsandathome.6Farmingtoomuchonpoorland.YouthinkYouhearListentothetapeagainandchoosethebestanswertoeachquestiononpage48.Answer:BABListeningtextWhydowehavedesertstoday?Desertshavenotalwaysbeenhere.Mostdesertsthatwehavetodaywereoncegreenlandsfulloftheplantlife.Oneoftoday’sbiggestdesertsisinNorthAfrica.However,inthe1stcenturyBCfarmsintheNorthAfricagrewcornandwheattomakebreadforthewholecityofRome.Howdidthisareabecomedesert?FIGHTINGGROWINGDESERTSBothweatherandpeoplecanhelpfromadesert.Hotweatherorverylittlerainmakesthelandsodrythatnothingcangrow.Ifpeoplecutdownorburntreesandplantstomakelandclearforfarming,thewindcanblowthesoilawayandturnthedrylandintosand.Anotherbigproblemisfarmingonlandthatisnotverygood.Thispoorlandcanveryquicklyturnintodesert,ifitisfarmedtoomuch.Oneofthebiggestcauses,however,iswhenpeopletaketheiranimalstothesamefieldstofeedoverandover,andthefieldsfinallylosealltheirnutrition.Becauseoftheseproblems,desertsareslowlytakingovergreenlandinmanypartsoftheworld,includingChina.However,wecanfightthegrowingdeserts!InsomepartsofChinapeopleareworkingtopreventdesertfromexpanding.InXinjiang,forexample,somefarmersaretryingnewscientificfarmingmethods.Thesemethodsmakeitpossibletouselesslandforcrops,sofarmersthencanplanttreesontherestoftheirland!OnXinjiangfarmer,usedonlyhalfofhisfieldstogrowthesameamountofcropsaslastyear.Ontheotherhalfofhisland,heplantedfruittrees.Theworkofpeoplelikethisishelpingtofighttheworld’sgrowingdeserts.SpeakingJiaSixie’sworkwaswritten1,600yearsago.Isitstillatallusefultoday?Inpairs,discussthefollowingquestionsandtakenotesonyourconclusions.1WhatideasinQiMinYaoShuarestillinfarmingtoday?2WhatproblemsdowehavetodayinmodernfarmingthatJiaSixiedidnothaveinhistime?WritingUsetheideasyoudiscussedabovetowriteareportabouthowusefulJiaSixie’sideasareformoderntimes.Usethestepsonpage53tohelpyou.1,600yearsagotheChinesewriterJiaSixiewroteabookQiMinYaoShuaboutgoodagriculturalpractices.TodaysomeofJiaSixie’sideasarestillveryusefultoourmoderntimes,butwehavesomeproblemstodaythatheneverhadinhistime.SamplewritingSomeofJiaSixie’sideasarestillveryusefultoourmoderntimes.Farmersstillcleartheirfieldsofweeds.Theystillploughdeeplythefirsttimeandlessdeeplythesecondtime.Inaddition,farmerseverywherestillunderstandthatchangingcropsinthefieldsisstillimportant.However,wehavesomeproblemstodaythatJiaSixieneverfacedinhistime.Wehaveenvironmentalpollutionthatharmsfieldsandcrops.Wehavegreatcompetitioninthemarketplace.Wehavenew,dangerousandpowerfulcropdiseases.AlthoughourmodernfarmersstillusesomeofJiaSixie’sideastoday,theyfaceproblemsthatwereneverheardofinJiaSixie’day.