填空题TacomaNarrowsBridge-DisasterStrikesWhentheTacomaNarrowsBridgeopenedfortrafficon1July1940,itwascelebratedasamajorengineeringachievement.Evenbeforeconstructionwascompleted,however,flawsinthedesignwereapparent;workerssuckedonlemonslicestoavoidmotionsicknessasthestructureswayedintherelativelymildwinds.Engineerstriedthreedifferentrevisionsduringconstructiontoaddressthevibrationproblem.Initially,tie-downcableswereanchoredtofifty-tonnebulkheadsontheriverbanks.Thesewereineffective,asthecablessoondetached.Thenapairofinclinedcablelockswasintroducedtoconnectthemaincablestothebridgedeckatmid-span.Thesestayedthroughoutthebridge"slifespan,butdidnothingtoreducevibration.Afurthermeasure—theinstallationofhydraulicdampersbetweenthetowersandthefloorsystem—wasnullifiedbecausethedamperswerecompromisedwhenthebridgewassand-blastedbeforepainting.Shortlyafteropening,thebridgequicklyacquiredthefondnicknameof"GallopingGertie"becauseofthewayitwouldrollineitherside-to-sideorlength-waysmovements—knowninphysicstermsasthelongitudinalandtransversemodesofvibrationrespectively.Thesemovementsdidnotcompromisethecoreintegrityofthestructure,butdidmakethecrossingasomewhatwhite-knuckleaffair.Manydriversreportedseeingcarsaheaddisappearfromsightseveraltimesastheysankintotroughsfromtransversevibrations(imaginetherippleacrossapackedstadiumduringaMexicanwave).Theexperienceofalongitudinalwaveiscloselyanalogous,butmoreaccuratelyassociatedwiththewavesonewouldencounterintheocean.Onasuspensionbridgethough,thesewavesareauniqueexperience—somedare-devilswerehappytopaythe75ctolljustforthethrill!Fourmonthslater,however,anever-before-seentypeofvibrationbeganafflictingthebridgeinwhatwerestillfairlygentlewinds(about40kmph).Ratherthanthesimple"wave"motionthatcharacteriseslongitudinalandtransversevibration,theleftsideofthebridgewouldrisewhiletherightsidefell,butthecentrelineoftheroadwouldremaincompletelylevel.Thiswasprovedwhentwomenwalkedalongthecentreofthebridgecompletelyunaffectedbytherockingmotionsaroundthem.Visuallythebridge"smovementsseemedtobemorelikeabutterflyflappingitswingsthanasimplerollingmotion.Engineersnowunderstandthistobethetorsionalmodeofvibration,anditisextremelyhardtodetect.Inaeroplanedesign,forexample,evenminuteshiftsoftheaircraft"smassdistributionandanalterationinonecomponentcanaffectacomponentwithwhichithasnologicalconnection.Initsmilderformsthiscancausealightbuzzingnoise,similartothatwhichawasporabumblebeemakes,butwhenallowedtodevelopuncheckeditcaneventuallycausethetotaldestructionofanaeroplane.Thetorsionalmodeofvibrationistheconsequenceofasetofactionsknownasaerostaticflutter.Thisinvolvesseveraldifferentelementsofastructureoscillatingfromtheeffectofwind,witheachcycleofflutteringbuildingmoreenergyintothebridge"smovementsandneutralisinganystructuraldampingeffects.Becausethewindpumpsinmoreenergythanthestructurecandissipate,andtheoscillationsfeedoffeachothertobecomeprogressivelystronger,theaerostaticflutteringandtorsionalvibrationswereallbutassuredtodestroytheTacomaBridgeonthemorningof7November.At11.00a.m.theflutteringhadincreasedtosuchamplitudethatthesuspendercableswereplacedunderexcessivestrain.Whenthesebuckled,theweightofthedecktransferredtotheadjacentcableswhichinturnwereunabletosupporttheweight.Thesecablesbuckled,leavingnothingtostopthecentraldeckbreakingoffintotheTacomaRiver.Itwasataround10.15a.m.on7Novemberthattorsionalvibrationbeganafflictingthebridge.Thismadedrivingtreacherous,andnewspapereditorLeonardCoatsworth"scarwasjammedagainstthecurbinthecentreofthebridgeasheattemptedtocross.Coatsworthtriedtorescuehisdaughter"scockerspanielfromthebackseatbutwasunsuccessful,andfearingforhislife,crawledandstaggeredtosafetyonhisown.Atthispoint,anengineeringprofessornamedBertFarquharsonproceededontothebridgeinanattempttosavethefrightenedanimal.Farquharsonhadbeenvideo-recordingfromthebanksoftheriverandhadjustreturnedfrompurchasingmorerollsoffilm.Asanavoweddogloverhefeltobligedtoattemptarescue.Unfortunately,theprofessortoowasbittenandretreatedemptyhanded,walkingoffjustmomentsbeforethecablessnappedandthegiantconcretemassofthecentraldeckcavedinwardsanddisappearedintotheriver.

填空题Questions1-5Completethediagrambelow.ChooseNOMORETHANTWOWORDSfromReadingPassage1foreachanswer.Writeyouranswersinboxes]-5onyouranswersheet.

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填空题Apart from Chinese, the NEP focuses on ______.

填空题Questions 33-40 Look at the following statements (Questions 33-40) and the list of people in the box below. Match each statement with the correct person A-D. Write the appropriate letter A-D in boxes 33-40 on your answer sheet. NB You may use any letter more than once. A．Gorse B．Beck C．Rifkin D．Fluorite

填空题25 pence per minute________

填空题Biological control entails using synthetic chemicals to try and change the genetic make-up of the pests' offspring.

填空题derive from

填空题Japanese children are generally cleverer than children from other countries, as Japan is among the largest fish-consuming countries.

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填空题Most countries believe learning about history should allow students to think for themselves.

填空题What kind of training does the company apply?

填空题The first stage of the process is __________ .

填空题Obtaining money to improve the lasers will depend on tests in real storms.

填空题Decide which TWO things David Price recommends doing 6 months before going abroad. You may write your answers in any order. Choose from the following list: A get a new passport B revalidate your passport C ensure your passport is valid for at least six months D get a visa for the country you are going to E ensure your passport is full F make sure your passport has some empty pages

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填空题What nationality are Martina"s new flatmates?

填空题Acreativeresponse—beinventive______

填空题{{I}}Complete the sentences below. Write {{B}}NO MORE THAN THREE WORDS{{/B}} for each answer.{{/I}}

填空题Mr Singh believes that Western methods plus the ______ are an excellent mix.