2015职称外语新增文章

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1、第九篇AnEssentialScientificProcessAlllifeontheearthdependsupongreenplants.Usingsunlight,theplantsproducetheirownfood.Thenanimalsfeedupontheplants.Theytakeinthenutrientstheplantshavemadeandstored.Butthat’snotall.Sunlightalsohelpsaplantproduceoxygen.Someoftheoxygenisusedbytheplant,

2、butaplantusuallyproducesmoreoxygenthanituses.Theexcessoxygenisnecessaryforanimalsandotherorganismstolive.Theprocessofchanginglightintofoodandoxygeniscalledphotosynthesis.Besideslightenergyfromthesun,plantsalsousewaterandcarbondioxide.Thewatergetstotheplantthroughitsroots.Theca

3、rbondioxideenterstheleavesthroughtinyopeningscalledstomata.Thecarbondioxidetravelstochloroplasts,specialcellsinthebodiesofgreenplants.Thisiswherephotosynthesistakesplace.Chloroplastscontainthechlorophyllsthatgiveplantstheirgreencolor.Thechlorophyllsarethemoleculesthattraplight

4、energy.Thetrappedlightenergychangeswaterandcarbondioxidetoproduceoxygenandasimplesugarcalledglucose.　　Carbondioxideandoxygenmoveintoandoutofthestomata.Watervaporalsomovesoutofthestomata.Morethan90percentofwateraplanttakesinthroughitsrootsescapesthroughthestomata.Duringthedayti

5、me,thestomataofmostplantsareopen.Thisallowscarbondioxidetoentertheleavesforphotosynthesis.Asnightfalls,carbondioxideisnotneeded.Thestomataofmostplantsclose.Waterlossstops.　　Ifphotosynthesisceased,therewouldbelittlefoodorotherorganicmatterontheearth.Mostorganismswoulddisappear.

6、Theearth’satmospherewouldnolongercontainoxygen.Photosynthesisisessentialforlifeonourplanet.　　词汇：　　nutrientn.营养物　　organismn.生物体，有机体　　carbondioxiden.二氧化碳　　chloroplastn.叶绿体　　moleculen.分子　　vaporn.水蒸气　　oxygenn.氧气　　photosynthesisn.光合作用　　chlorophylln.叶绿素　　glucosen.葡萄糖　　ceasev.停止　　注释：

7、　　1.Thenanimalsfeedupontheplants.动物以植物为食。　　练习：　　1.Inthefirstparagraph，theword“excess”means　　A　heavy.　　B　extra.　　C　green.　　D　liquid.　　2.Whichofthefollowingdoesnotmovethroughaplant’sstomata?　　A　Carbondioxide.　　B　Watervapor.　　C　Oxygen.　　D　Food.　　3.Inthetitle,thetermEssentialScien

8、tificProcessrefersto　　A　photosynthesis.　　B　theformationofgluc