Whileintegrasedeletesanimmunecell'sgeneticmaterialandreplacesitwithitsown,itactslike________inawordprocessor.

Passage4

Questions16to20arebasedonthefollowingpassage:

Cultureshockisanoccupationaldisease(职业病)forpeoplewhohavebeensuddenlytransplantedabroad.

Cultureshockiscausedbytheanxietythatresultsfromlosingallfamiliarsignsandsymbolsofsocialintercourse.Thosesignsareasfollowing:whentoshakehandsandwhattosaywhenmeetpeople,whenandhowtogivetips,howtomakepurchases,whentoacceptandrefuseinvitations,whentotakestatementsseriouslyandwhennot.Thesesigns,whichmaybewords,gestures,facialexpressions,orcustoms,areacquiredbyallofusinthecourseofgrowingupandasmuchapartofourcultureasthelanguagewespeakorthebeliefsweaccept.Allofusdependonhundredsofthesesignsforourpeaceofmindandday-to-dayefficiency,butwedonotcarrymostatthelevelofconsciousawareness.

Nowwhenanindividualentersastrangeculture,allormostofthesefamiliarsignsareremoved.Nomatterhowbroadmindedorfullofgoodwillyoumaybeaseriesofsupportshavebeenknockedfromunderyou,followedbyafeelingoffrustration.Whensufferingfromcultureshockpeoplefirstrejecttheenvironmentwhichcauseddiscomfort.Thewaysofthehostcountryarebadbecausetheymakeusfeelbad.Whenforeignersinastrangelandgettogetherincomplainaboutthehostcountryitspeople,youcanbesurethattheyaresufferingfromcultureshock.

16.Accordingtothepassage,cultureshockis.

A.anoccupationaldiseaseofforeignpeopleB.mayleadtoveryserioussymptoms

C.actuallynotadiseaseD.incurable

17.Accordingtothepassage,cultureshockresultfrom.

A.thesuddenchangeofsocialatmosphereandcustoms

B.thesuddenchangeofourdailyhabits

C.thesuddenlossofourownsignsandsymbols

D.thediscomfortthatwefeelwhenfacedwithaforeigner

18.Whichoneofthefollowingmaynotbeasymptomofcultureshock?

A.Youdon’tknowhowtoexpressyourgratitude.

B.Youdon’tknowhowtogreetotherpeople.

C.Yousuddenlyforgetwhatawordmeans.

D.Youdon’tunderstandwhyaforeignershrugs.

19.Accordingtothepassage,howwouldapersonwhostaysabroadmostprobablyreactwhenheisfrustratedbythecultureshock?

A.Heismostlikelytorefusetoabsorbthestrangeenvironmentatfirst.

B.Heisreallytoacceptthechangeandadapthimselftothenewenvironment.

C.Althoughhetakestheculturedifferenceforgranted,hestilldoesn’tknowhowtodowithit.

D.Hemaybegintohatethepeopleorthingsaroundhim.

20.Themainideaofthispassageisthat.

A.cultureshockisanoccupationaldisease

B.cultureshockiscausedbytheanxietyoflivinginastrangeculture

C.cultureshockhaspeculiarsymptoms

D.itisveryhardtocopewithlifeinanewsetting

Whichissafer-stayingathome，travelingtoworkonpublictransport，orworkingintheoffice?Surprisingly，eachofthesecarriesthesamerisk，whichisverylow.However，whataboutflyingcomparedtoworkinginthechemicalindustry?Unfortunately，theformeris65timesriskierthanthelatter!Infact，theaccidentrateofworkersinthechemicalindustryislessthanthatofalmostanyofhumanactivity，andalmostassafeasstayingathome.

Thetroublewiththechemicalindustryisthatwhenthingsgowrongtheyoftencausedeathtothoselivingnearby.Itisthiswhichmakeschemicalaccidentssonewsworthy.Fortunately，theyareextremelyrare.ThemostfamousoneshappenedatTexasCity(1947)，Flixborough(1974)，Seveso(1976)，Pemex(1984)andBhopal(1984)。

Someofthesearealwaysinthemindsofthepeopleeventhoughthelossoflifewassmall.NoonediedatSeveso，andonly28workersatFlixborough.TheworstaccidentofallwasBhopal，whereupto3，000werekilled.TheTexasCityexplosionoffertilizerkilled552.ThePemexfireatastorageplantfornaturalgasinthesuburbsofMexicoCitytook542lives，justamonthbeforetheunfortunateeventatBhopal.

Someexpertshavediscussedtheseaccidentsandusedeachaccidenttoillustrateaparticulardanger.ThustheTexasCityexplosionwascausedbytonsofammoniumnitrate(硝酸铵)，whichissafeunlessstoredingreatquantity.TheFlixboroughfireballwasthefaultofmanagement，whichtookriskstokeepproductiongoingduringessentialrepairs.TheSevesoaccidentshowswhathappensifthelocalauthoritieslackknowledgeofthedangerontheirdoorstep.Whenthepoisonousgasdriftedoverthetown，localleaderswereincapableoftakingeffectiveaction.ThePemexfirewasmadeworsebyanoverloadedsiteinanovercrowdedsuburb.Thefiresetoffachainreactionosexplodingstoragetanks.Yet，byamiracle，thetwolargesttanksdidnotexplode.Hadthesecaughtfire，then3，000strongrescueteamandfirefighterswouldallhavedied.

1.Chemicalaccidentsareusuallyimportantenoughtobereportedasnewsbecause____.

A.theyareveryrare

B.theyoftencauselossoflife

C.theyalwaysoccurinbigcities

D.theyarousetheinterestofallthereaders

2.Whichofthefollowingstatementsistrue?

A.Workingattheofficeissaferthanstayingathome.

B.Traverllingtoworkonpublictransportissaferthanworkingattheoffice.

C.Stayingathomeissaferthanworkinginthechemicalindustry.

D.Workinginthechemicalindustryissaferthantravelingbyair.

3.Accordingtopassage，thechemicalaccidentthatcausedbythefaultofmanagementhappenedat____.

A.TexascityB.FlixboroughC.SevesoD.MexicoCity

4.Fromthediscussionamongsomeexpertswemaycocludethat____.

A.toavoidanyaccidentsweshouldnotrepairthefacilitiesinchemicalindustry

B.thelocalauthoritiesshouldnotbeconcernedwiththeproductionofthechemicalindustry

C.alltheseaccidentscouldhavebeenavoidedorcontrolledifeffectivemeasurehadbeentaken

D.naturalgasstoredinverylargetanksisalwayssafe

5.Fromthepassageweknowthatammoniumnitrateisakindof____.

A.naturalgas，whichcaneasilycatchfire

B.fertilizer，whichcan'tbestoredinagreatquantity

C.poisonoussubstance，whichcan'tbeusedinovercrowdedareas

D.fuel，whichisstoredinlargetanks

PartVWriting

写作指导

这是一篇描写文(Description)。用通俗的话说，描写文就是用文字给人物、地点、景物画象。一篇描写文主要是通过所感受的细节——所见所闻发展而来的。在写人时，不仅仅要用细节描写其外貌，而要注重通过他的言行来表现其人物性格、思想和品德，更要抓住他区别于他人的性格特点，这样就容易给读者留下深刻的印象。短文的第一、二段叙述故事发生的时间、地点，故事发生的原因及故事所涉及的人物。文章的三、四、五段描写的是人物的外貌，穿着及性格特点。通过对人物言行的简单描写来揭示主人翁的助人为乐的高尚精神。短文的最后一段，要用一句话概括作者对主人翁的看法：Agoodguy。文章有描述，有议论，要加叙加议，有血有肉，上下文连贯要紧密，首尾要呼应，人和事要给人们留下深刻印象。

Recentresearchhasclaimedthatanexcessofpositiveionsintheaircanhaveanilleffectonpeople’sphysicalorpsychologicalhealth.Whatarepositiveions?Well,theairisfullofions,electricallychargedparticles,andgenerallythereisaroughbalancebetweenthepositiveandthenegativecharged.Butsometimesthisbalancebecomesdisturbedandalargerproportionofpositiveionsarefound.Thishappensnaturallybeforethunderstorm,earthquakeswhenwindssuchastheMistral,HamsinorSharavareblowingincertaincountries.Oritcanbecausedbyabuild-upofstaticelectricityindoorsfromcarpetsorclothingmadeofman-madefibres,orfromTVsets,duplicatorsorcomputerdisplayscreens.

Whenalargenumberofpositiveionsarepresentintheairmanypeopleexperienceunpleasanteffectssuchasheadaches,fatigue,irritability,andsomesensitivepeoplesuffernauseaorevenmentaldisturbance.Animalsarealsoaffected,particularlybeforeearthquakes,snakeshavebeenobservedtocomeoutofhibernation,ratstofleefromtheirburrows,dogshowlandcatsjumpaboutunaccountably.ThishasledtheUSGeographicalSurveytofundanetworkofvolunteerstowatchanimalsinanefforttoforeseesuchdisastersbeforetheyhitvulnerableareassuchasCalifornia.

Conversely,whenlargenumbersofnegativeionsarepresent,thenpeoplehaveafeelingofwell-being.Naturalconditionsthatproducetheselargeamountsarenearthesea,closetowaterfallsorfountains,orinanyplacewherewaterissprayed,orformsaspray.Thisprobablyaccountsforthebeneficialeffectofaholidaybythesea,orinthemountainswithtumblingstreamsorwaterfalls.

Toincreasethesupplyofnegativeionsindoors,somescientistsrecommendtheuseofionisers:smallportablemachines,whichgeneratenegativeions.Theyclaimthationisersnotonlycleanandrefreshtheairbutalsoimprovethehealthofpeoplesensitivetoexcesspositiveions.Ofcourse,therearethedetractors,otherscientists,whodismisssuchclaimsandareskepticalaboutnegative/positiveionresearch.Thereforepeoplecanonlymakeuptheirownmindsbyobservingtheeffectsonthemselves,oronothers,ofanegativerichorpoorenvironment.Afterallitisdebatablewhetherdependingonseismicreadingstoanticipateearthquakesismoreeffectivethanwatchingthecat.

1.Whateffectdoesexceedingpositiveionizationhaveonsomepeople?

A.Theythinktheyareinsane.

B.Theyfeelratherbad-temperedandshort-fussed.

C.Theybecomeviolentlysick.

D.Theyaretootiredtodoanything.

2.Inaccordancewiththepassage,staticelectricitycanbecausedby___.

A.usinghome-madeelectricalgoods.

B.wearingclothesmadeofnaturalmaterials.

C.walkingonartificialfloorcoverings.

D.copyingTVprogramsonacomputer.

3.Ahighnegativeioncountislikelytobefound___.

A.nearapoundwithawaterpump.

B.closetoaslow-flowingriver.

C.highinsomebarrenmountains.

D.byarotatingwatersprinkler.

4.Whatkindofmachinecangeneratenegativeionsindoors?

A.Ionisers.

B.Air-conditioners.

C.Exhaust-fans

D.Vacuumpumps.

5.Somescientistsbelievethat___.

A.watchinganimalstoanticipateearthquakesismoreeffectivethandependingonseismography.

B.theunusualbehaviorofanimalscannotbetrusted.

C.neitherwatchingnorusingseismographsisreliable.

D.earthquake