课时作业： 选修七 unit 3

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1、Ⅰ.阅读理解A体裁：说明文　话题：海洋　词数：318　时间：7′Theseaishometobillionsofplantsandanimals.Manyliveonlynearthesunlitsurface.Oceanographersclassifymarinelivingbeingsbyseparatingthemintotwomaingroups：plantsandanimals.Therearetwogeneraltypesofplantsfoundintheocean，thosehavi

2、ngrootsthatareattachedtotheoceanbottomandthosenothavingrootswhichsimplydriftaboutwiththewater.Therootedplantsintheoceanareonlyfoundinshallowwaterbecausethereisnotenoughsunlighttosustainphotosynthesis(光合作用)indeeperwaters.Sincesunlightdoesnotpassmorethana

3、fewhundredfeetintotheocean，mostoftheoceanisnotcapableofsupportingrootedplants.Themostplentyplantsintheoceanareknownasphytoplankton(浮游生物)．Theseareusuallysingle－celled，minutefloatingplantsthatdriftthroughoutthesurfacewatersoftheocean.Togrow，phytoplanktonn

4、eednutrientsfromtheseawaterandlotsofsunlight.Marineanimalsaredividedintothreegroups：zooplankton，nekton，andbenthos.Zooplanktonaredriftinganimalsandareusuallysmall，however，theycangrowtofairlylargesize.Forexample，thejellyfishandthePortugueseman－of－warareex

5、amplesoflargertypesofzooplanktonwhichareunabletopropel(推进)themselveseffectively.Nektonarethefreeswimmersandprobablythelargestportionoffamiliaranimalsfoundintheoceanbelongtothisclass.Commonfishes，theoctopus，whales，eelsandsquidareallexamplesofnekton.Theth

6、irdtypeofseaanimalsspendsitsentirelifeonorintheoceanbottom.Thisgroupofmarineanimalsiscalledthebenthos.Someofthesecreatures，suchaslobstersandsnails，maybeabletomoveaboutonthebottombuttheirlifestyleissoboundupwiththeoceanfloorthattheyareunabletosurviveaway

7、fromthisenvironment.【语篇解读】　海洋是成千上万种动物和植物的家乡。海洋植物主要有两种：有根植物和浮游植物；海洋动物大体可分为三类：浮游动物、游泳动物和海底动物。1．Thetextmainlytellsussomethingabout________．A．marineplantsandmarineanimalsB．twotypesofseaplantsC．threekindsofseaanimalsD．smallandbiganimalsintheocean答案　A　[主旨大意题。

8、本文主要讲述了海洋生物的分类(海洋植物和海洋动物)以及他们的特点。]2．Whycan'twefindtherootedplantsindeepwateroftheocean?A．Becausetherearetoomanyrocksatthebottomoftheocean.B．Becausetherootedplantscan'tstandthecoldnessoftheocean.C．Becausethereisnotenoughsunlightfo