单选题 PassageFour Questions16to20arebasedonthefollowingpassage. Aroundtheworldmoreandmorepeoplearetakingpartindangeroussportsandactivities.Ofcourse,therehavealwaysbeenpeoplewhohavelookedforadventure----thosewhohaveclimbedthehighestmountains,exploredunknownpartsoftheworldorsailedinsmallboatsacrossthegreatestoceans.{{U}}Now,however,therearepeoplewhoseekanimmediatethrillfromariskyactivitywhichmayonlylastafewminutesorevenseconds.{{/U}} Iwouldconsiderbungeejumpingtobeagoodexampleofsuchanactivity.Youjumpfromahighplace(perhapsabridge,orahot-airballoon)200metresabovethegroundwithanelasticropetiedtoyourankles.Youfallatupto150kilometresanhourtilltheropestopsyoufromhittingtheground.Itisestimatedthat2millionpeoplearoundtheworldhavenowtriedbungeejumping.Otheractivitiesasriskyasbungeejumpinginvolvejumpingfromtallbuildingsanddivingintotheseafromthetopofhighcliffs.Whydopeopletakepartinsuchactivitiesasthese?Somepsychologistssuggestthatitisbecauselifeinmodernsocietieshasbecomesafeandboring.Notverylongago,people’sliveswereconstantlyunderthreat.Theyhadtogooutandhuntforfood,diseasescouldnoteasilybecured,andlifewasacontinuousbattleforsurvival. Nowadays,accordingtomanypeople,lifeofferslittleexcitement.Theyliveandworkinacomparativelysafeenvironment;theybuyfoodinshops,andthereare doctorsandhospitalstolookafterthemiftheybecomeill.Theanswerforsomeofthesepeopleistoseekdangerinactivitiessuchasbungeejumping.