英语学习六级真题必备.docx

英语学习六级真题必备.docx

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英语学习六级真题必备

弃我去者，昨日之日不可留

乱我心者，今日之日多烦忧

大学英语六级考试真题（A卷）

PartIwriting（30minutes）

注意：

此部分试题在答题卡1上

PartIIReadingComprehension（Skimmingandscanning）（15minutes）

Supersizesurprise

Askanyonewhythereisanobesityepidemicandtheywilltellyouthatit’saldowntoeatingtoomuchandburningtoofewcalories.Thatexplanationappealstocommonsenseandhasdominatedeffortstogettotherootoftheobesityepidemicandreverseit/yetobesityresearchersareincreasinglydissatisfiedwithit.Manynowbelievethatsomethingelsemusthavechangedinourenvironmenttoprecipitate（促成）suchdramaticrisesinobesityoverthepast40yearsorso.Nobodyissayingthatthe“bigtwo”–reducedphysicalactivityandincreasedavailabilityoffood–arenotimportantcontributorstotheepidemic,buttheycannotexplainitall.

Earlierthisyearareviewpaperby20obesityexpertssetoutthe7mostplausiblealternativeexplanationsfortheepidemic.Heretheyare.

1.Notenoughsleep

Itiswidelybelievedthatsleepisforthebrain,notthebody.Couldashortageofshut-eyealsobehelpingtomakeusfat?

Severallarge-scalestudiessuggesttheremaybealink.Peoplewhosleeplessthan7hoursanighttendtohaveahigherbodymassindexthanpeoplewhosleepmore,accordingtodatagatheredbytheUSNationalHealthandNutritionExaminationSurvey.Similarly,theUSNurses’HealthStudy,whichtracked68,000womenfor16years,foundthatthosewhosleptanaverageof5hoursanightgainedmoreweightduringthestudyperiodthanwomenwhoslept6hours,whointurngainedmorethanwhosewhoslept7.

It’swellknownthatobesityimpairssleep,soperhapspeoplegetfatfirstandsleeplessafterwards.Butthenurses’studysuggeststhatitcanworkintheotherdirectiontoo:

sleeplossmayprecipitateweightgain.

Althoughgettingfiguresisdifficult,itappearsthatwereallyaresleepingless.In1960peopleintheUSsleptanaverageof8.5hourspernight.A2002pollbytheNationalSleepFoundationsuggeststhattheaveragehasfallentounder7hours,andthedeclineismirroredbytheincreaseinobesity.

2.Climatecontrol

Wehumans,likeallwarm-bloodedanimals,cankeepourcorebodytemperaturesprettymuchconstantregardlessofwhat’sgoingonintheworldaroundus.Wedothisbyalteringourmetabolic（新陈代新的）rate,shiveringorsweating.Keepingwarmandstayingcooltakeenergyunlessweareinthe“thermo-neutralzone”,whichisincreasinglywherewechoosetoliveandwork.

Thereisnodenyingthatambienttemperatures（环境温度）havechangedinthepastfewdecades.Between1970and2000,theaverageBritishhomewarmedfromachilly13Cto18C.IntheUS,thechangeshavebeenattheotherendofthethermometerastheproportionofhomeswithairconditioningsrosefrom23%to47%between1978and1997.Inthesouthernstates–whereobesityratestendtobehighest–thenumberofhouseswithairconditioninghasshotupto71%from37%in1978.

Couldairconditioninginsummerandheatinginwinterreallymakeadifferencetoourweight?

Sadly，thereissomeevidencethatitdoes-atleastwithregardtoheating.Studiesshowthatincomfortabletemperaturesweuselessenergy.

3.Lesssmoking

Badnews:

smokersreallydotendtobethinnerthantherestofus,andquittingreallydoespackonthepounds,thoughnooneisnsurewhy.Itprobablyhassomethingtodowiththefactthatnicotineisanappetitesuppressantandappearstoupyourmetabolicrate.

KatherineFlegalandcolleagresattheUSNationalCenterforHealthStatisticsinHyattsville,Maryland,havecalculatedthatpeoplekickingthehabithavebeenrespousibleforasmallbutsignificantportionoftheUSepidemicoffatness.Fromdatacollectedaroud1991bytheUSNationalHealthandNutritionExaminationSurvey,theyworkedoutthatpeoplewhohadquitinthepreviousdecadeweremuchmorelikelytobeoverweightthansmokersandpeoplewhohadneversmoked.Amongmen,forexample,nearlyhalfofquitterswereoverweightcomparedwith37%ofnon-smokersandonly28%ofsmokers.

4.Geneticeffects

Yourschancesofbecomingfatmaybeset,atleastinpart,beforeyouwereevenborn.childrenofboesemothersaremuchmorelikelytobecomeobestthemselveslaterinlife.Offspringofmicefedahigh-fatdietduringpregnancyaremuchmorelikelytobecomefatthantheoffspringofidenticalmicefedanormaldiet.Intriguingly,theeffectpersistsfortwoorthreegenerations.Grand-childrenofmicefedahigh-fatdietgrowupfateveniftheirownmotherisfednormally-soyoufatemayhavebeensealedevenbeforeyouwereconceived.

5.Alittleolder…

Somegroupsofpeoplejusthappentobefatterthanothers.surveyscarriedoutbytheUSnationalcenterforhealthstatistiesfoundthatadultsaged40to79werearoundthreetimesaslikelytobeobeseasyoungerpeople.non-whitefemalesa