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ID:40645188
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时间:2019-08-05
《理工类C级 阅读理解》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、理工类C级阅读理解 第九篇AnEssentialScientificProcess Alllifeontheearthdependsupongreenplants.Usingsunlight,theplantsproducetheirownfood.Thenanimalsfeedupontheplants.Theytakeinthenutrientstheplantshavemadeandstored.Butthat’snotall.Sunlightalsohelpsaplantproduceo
2、xygen.Someoftheoxygenisusedbytheplant,butaplantusuallyproducesmoreoxygenthanituses.Theexcessoxygenisnecessaryforanimalsandotherorganismstolive. Theprocessofchanginglightintofoodandoxygeniscalledphotosynthesis.Besideslightenergyfromthesun,plantsalsouse
3、waterandcarbondioxide.Thewatergetstotheplantthroughitsroots.Thecarbondioxideenterstheleavesthroughtinyopeningscalledstomata.Thecarbondioxidetravelstochloroplasts,specialcellsinthebodiesofgreenplants.Thisiswherephotosynthesistakesplace.Chloroplastsconta
4、inthechlorophyllsthatgiveplantstheirgreencolor.Thechlorophyllsarethemoleculesthattraplightenergy.Thetrappedlightenergychangeswaterandcarbondioxidetoproduceoxygenandasimplesugarcalledglucose. Carbondioxideandoxygenmoveintoandoutofthestomata.Watervapora
5、lsomovesoutofthestomata.Morethan90percentofwateraplanttakesinthroughitsrootsescapesthroughthestomata.Duringthedaytime,thestomataofmostplantsareopen.Thisallowscarbondioxidetoentertheleavesforphotosynthesis.Asnightfalls,carbondioxideisnotneeded.Thestomat
6、aofmostplantsclose.Waterlossstops. Ifphotosynthesisceased,therewouldbelittlefoodorotherorganicmatterontheearth.Mostorganismswoulddisappear.Theearth’satmospherewouldnolongercontainoxygen.Photosynthesisisessentialforlifeonourplanet. 词汇: nutrientn.营养物
7、 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: 1.Thenanimalsfeedupontheplants.动物以植物为食。 练习: 1.Inthefirstparagraph,theword“excess”me
8、ans A heavy. B extra. C green. D liquid. 2.Whichofthefollowingdoesnotmovethroughaplant’sstomata? A Carbondioxide. B Watervapor. C Oxygen. D Food. 3.Inthetitle,thetermEssentialScientificProcessrefersto A photosynthesis. B the
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