大学英语考试复习资料大学四级模拟173.docx
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大学英语考试复习资料大学四级模拟173.docx
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大学英语考试复习资料大学四级模拟173
[大学英语考试复习资料]大学四级模拟173
大学四级模拟173
PartⅠWriting
Directions:
Forthispart,youareallowed30minutestowritealettertoafriendwhowillcometoyourcitytoseeyou.Youshouldwriteatleast120wordsfollowingtheoutlinegivenbelow:
问题:
1.假设你是王红。
你的一个朋友准备到你所在的城市来旅游,但你有事不能接待他/她。
写封信给他/她,解释你不能接待的原因,并说明你对他/她的安排。
答案:
SampleWriting:
DearTina,
I'mgladtoknowthatyouarecomingtomycityforvacationsoon,andI'msureyouwillhaveagoodtimehere.
However,I'mafraidthere'ssomebadnews.I'mplanningtotakepartinaninternationalconferencetobeheldinanothercityduringthetimeofyourvisit.Allthetopscientistsinmyfieldwillshowupattheconference,andmoreimportantly,I'mluckyenoughtohavebeenselectedtogiveaspeechonbehalfofmyresearchteamattheconference.Ireallycan'tmissit.
Iunderstandthatit'llbeyourfirsttimetothiscityandI'myouronlyfriendhere.I'veaskedmyroommatetomeetyouattheairport,andyoucanstayinmyroom.Sheisaverynicepersonandshetoldmeshe'smorethanwillingtoshowyouaroundthecity.Hopeyoutwowillgetonwellandhaveaniceholiday!
Yours
Hong
PartⅡReadingComprehension(SkimmingandScanning)
Directions:
Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswerSheet1.
Forquestions1-7mark
Y(forYES)ifthestatementagreeswiththeinformationgiveninthepassage;
N(forNO)ifthestatementcontradictstheinformationgiveninthepassage;
NG(forNOTGIVEN)iftheinformationisnotgiveninthepassage.
Forquestions8-10,completethesentenceswiththeinformationgiveninthepassage.
CreaturesoftheThermalVents(海底热泉区)
Thethree-personsubmersibleAlvinsankthroughthecold,darkwatersofthePacificOceanformorethananhour,finallytouchingdownontheseafloormorethan8,000feetbelowthesurface.ItwasDecember1993,andthescientistsinsidethesubhadcometothisstretchoftheEastPacificRise,anunderwatermountainrangeabout500milessouthwestofAcapulco,Mexico,toinspectarecentlyformedhydrothermalvent—afissure(裂缝)intheoceanbottomthatleaksscalding(滚烫的),acidicwater.
Peeringoutthroughthesub'stinywindows,thevisitorswereastonishedtoseethicketsofgianttubeworms,somefourfeettall.Thetailendsofthewormswerefirmlyplantedontheoceanfloor,whileredplumesontheotherendsswayedlikeafieldofpoppies.Alvinhadbroughtresearcherstothesamespotlessthantwoyearsearlier,whentheyhadseennoneofthesestrangecreatures.Previousmeasurementsshowedthatindividualtubewormscouldincreaseinlengthatarateof33inchesperyear,maltingthemthefastest-growingmarineinvertebrates.Thatmeanstubewormscangrowmorerapidlythanscientistsoncethought.
Thegianttubewormisoneofthemostconspicuousmembersofadiversecommunitythatformsaroundhydrothermalvents.Scientistsoncethoughtthatnolivingthingcouldsurvivetheharshcombinationoftoxicchemicals,hightemperatures,highpressures,andtotaldarknessatthesevents.Butin1977,researchersdivinginAlvindiscoveredtubewormsandotherbizarreorganismsthrivingataventofftheGalapagosIslands.Similarcommunitieshavesincebeenfoundatseveralhundredhotspotsaroundtheworld.ThesecreaturesarelikenothingelseonEarth.
Ventsformwheretheplanet'scrystalplatesareslowlyspreadingapartandmagma(岩浆)iswellingupfrombelowtoformmountainrangesknownasmid-oceanridges.Ascracksformatthesespreadingcenters,seawaterseepsamileortwodownintothehotrock.Enrichedwithmineralsleachedfromtherock,thewaterheatsandrisestotheoceanfloortoformavent.Ventsareusuallyclusteredinfields,underwaterversionsofYellowstone'sgeyser(间歇泉)basins.Individualventopeningstypicallyragefromlessthanahalfinchtomorethansixfeetindiameter.Suchfieldsarenormallyfoundatadepthofmorethanamile.MosthavebeendiscoveredalongthecrestoftheMid-OceanicRidge,a46,000-mile-longchainofmountainsthatwrapsaroundEarthliketheseamsonabaseball.Afewventshavealsobeenfoundatseamounts(海底山),underwatervolcanoesthatarenotlocatedattheintersectionofcrystalplates.
Hydrothermalventsprovidehabitatformanycreaturesthatarenotfoundanywhereelseintheocean.Waterpouringoutofventscanreachtemperaturesuptoabout400℃;thehighpressurekeepsthewaterfromboiling.However,theintenseheatislimitedtoasmallarea.Withinlessthananinchoftheventopening,thewatertemperaturedropsto2℃.Mostofthecreaturesthatcongregatearoundventsliveattemperaturesjustabovefreezing.Thus,chemicalsarethekeytoventlife,notheat.Themostprevalentchemicaldissolvedinventwaterishydrogensulfide(硫化氢),whichsmellslikerotteneggs.Thischemicalisproducedwhenseawaterreactswithsulfateintherocksbelowtheoceanfloor.Ventbacteriausehydrogensulfideastheirenergysourceinsteadofsunlight.Thebacteriainturnsustainlargerorganismsintheventcommunity.
Theclams(蛤),mussels,tubeworms,andothercreaturesattheventhaveasymbioticrelationshipwithbacteria.Thegianttubeworms,forexample,havenodigestivesystem—nomouthorgut.Thewormdependsvirtuallysolelyonthebacteriaforitsnutritionandbothpartnersbenefit.Thebrown,spongytissuefillingtheinsideofatubewormispackedwithbacteria—about285billionbacteriaperounceoftissue.Theplumesatthetopoftheworm'sbodyareredbecausetheyarefilledwithblood,whichcontainshemoglobin(血色素)thatbindshydrogensulfideandtransportsittothebacteriahousedinsidetheworm.Inreturn,thebacteriaoxidizethehydrogensulfideandconvertcarbondioxideintocarboncompoundsthatnourishtheworm.
Tubewormsreproducebyspawning(产卵):
Theyreleasespermandeggs,whichcombineinthewatertocreateanewworm.Biologistsdon'tknowhowtheinfantwormacquiresitsownbacteria.Perhapstheeggcomeswithastarterset.Scientistsalsodon'tknowhowtubewormsandotherorganismslocatenewvents.Theventsaresmall,andtheyareseparatedlikeislands.Mostventorganismshaveafreeswimminglarvalstage.Butscientistsaren'tsurewhetherthelarvaefloataimlesslyorpurposelyfollowclues—suchaschemicaltracesinthewater—tofindnewhomes.
Studyingthelifecycleofventorganismsisdifficult.Researchershavevisitedonlyafraction(小部分)oftheocean'shotspots.Theyhavebeenabletoobserveventlifeonlybyshiningbrightlightsoncreaturesaccustomedtoinkydarkness,andmanyspecimensdiequicklywhenremovedfromtheiruniqueenvironment.Underwatercamerasarehelpingscientistsmakelessintrusiveobservations,butdivingexpeditionsarestillthemostusefulwaytogatherinformation.The1993AlvinexpeditiontotheEastPacificRisewasoneinaseriesofdivestothearea.
Thesitewasfirstvisitedin1989,andscientistsobservedventorganismsthrivingthere.ButwhenAlvinreturnedtwoyearslater,itsoccupantswitnessedthebirthofahydrothermalvent.Arecentvolcaniceruptionhadspreadglassylavaacrosstheoceanfloor,andtheresearchersmeasuredtemperaturesupto403℃—thehottesteverrecordedatahydrothermalvent.
"Themostspectacularsightdowntherewasthismassiveblindingsnowstormofbacteria,"saysRichLutz,amarineecologistatRutgersUniversity,wholedtheexpedition.Ontheoceanfloor,thebacteriaformedmatsseveralinchesthick,butthescientistssawnootherlivingthings.Sincetheeruption,scientistshavebeenabletowatchseveralstagesofcolonizationatthesite.WhentheyreturnedinMarch1992,onlyafewbacterialmatsremained.IntheirplacewerecoloniesofJerichowormsandavarietyofsmallcrustaceans.InDecember1993,thescientistsfirstobservedthegianttubewormsthere.ThescientistsnamedtheareaPhoenix,becausenewlifehadarisenfromtheashesoftheeruption.
1.Nolivingthingcouldsurviveataventexcepttubeworms.
答案:
NNolivingthingcouldsurviveataventexcepttubeworms.本题根据关键词tubeworms可以定位到原文第二段,如果仅仅阅渎本段可能会选NG或者Y。
但注意第二段并不是本题的出处,第三段才是。
阅读第二段即可知选N。
2.Tubewormscan'tliveinhigh-temperatureenvironment.
答案:
NTubewormscan'tliveinhigh-temperatureenvironment.同样在原文第三段可以看到本题的出处,上面说科学家们原本以为在充满有毒物质、高温、高压和完全黑暗的环境中不会有生命存在,但1977年他们发现了tubeworms。
选N。
3.Itischemicalsthatsustainventlife.
答案:
YItischemicalsthatsustainventlife.在第五段可以看到这句话“Thus,chemicalsarethekeytoventlife,notheat.”因此可知选Y。
4.Thebacteriadependonwormsforhydrogensulfideinthesymbioticrelationship.
答案:
YThebacteriadependonwormsforhydrogensulfideinthesymbioticrelationship.在原文第六段末有一句“Theplumesatthetopoftheworm'sbodyareredbecausetheyarefilledwithblood,whichcontainshemoglobinthatbindshydrogensulfideandtransportsittothebacteriahousedinsidetheworm.”根据本句可知是Y。
5.Whenanewventforms,tubewormscongregatearounditvoluntarily.
答案:
NGWhenanewventforms,tubewormscongregatearounditvoluntarily.根据关键词定位到第七段,原文这句话“Scientistsalsodon'tknowhowtubewormsandotherorganismslocatenewvents.”以及“Butscientistsaren'tsurewhetherthelarvaefloataimlesslyorpurposelyfollowclues…”,可知科学家并不知道tubeworms是如何寻找vent的,选NG。
6.Ventlifediesquicklywhenexposedtolight.
答案:
NGVentlifediesquicklywhenexposedtolight.阅读原文第八段可知,文章只是提到把某些种类移开固有的生活环境就会死亡,但是并没有说遇到光就会死亡,因此是NG。
7.Before1990,nogianttubewormswerefoundinPhoenix.
答案:
YBeforel990,nogianttubewormswerefoundinPhoenix.从原文最后一段最后一句可知,科学家在1993年才发现了gianttubeworms。
因此是Y。
8.Themajorityoflivingthingsthatgatheraroundventsliveattemperatures
答案:
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