【Aprofessorbeganhisclassbyholdingupaglasswithsomewaterinit.Hehelditupforalltoseeandaskedthestudents"Howmuchdoyouthinkthisglassweighs?""50grams!""100grams!""125grams!"thestudentsanswered."Ireallydon】

　　Aprofessorbeganhisclassbyholdingupaglasswithsomewaterinit.Hehelditupforalltoseeandaskedthestudents"Howmuchdoyouthinkthisglassweighs?"

　　"50grams!""100grams!""125grams!"thestudentsanswered.

　　"Ireallydon'tknowunlessIweighit"saidtheprofessor"butmyquestionis:WhatwouldhappenifIheldituplikethisforafewminutes?"

　　"Nothing"thestudentssaid.

　　"OKwhatwouldhappenifIheldituplikethisforanhour?"theprofessorasked.

　　"Yourarmwouldbegintoache"saidoneofthestudents.

　　"YouarerightnowwhatwouldhappenifIhelditupforaday?"

　　"Yourarmcouldgonumb(麻木的)andyoumighthavetogotohospital"anotherstudentsaid.

　　"Verygood!Butduringallthisdidtheweightoftheglasschange?"askedtheprofessor.

　　"NO"

　　"Thenwhatmadethearmacheandthemuscle(肌肉)stress?"

　　Thestudentswerepuzzled.

　　"Puttheglassdown"saidoneofthestudents.

　　"Exactly!"saidtheprofessor."Life'sproblemsaresomethinglikethis.HoldthemforminutesinyourheadandtheyseemOK.Thinkofthemforalongtimeandtheybegintoache.Holdthemevenlongerandtheybegintotroubleyou.Youwillnotbeabletodoanything.It'simportanttothinkoftheproblemsinyourlifebutevenmoreimportantto'putthemdown'attheendofeverydaybeforeyougotosleep.Thatwayyouarenotstressed;youwakeupeverydayfreshandstrongandcanhandleanyissueanychallengethatcomesyourway!"

　　根据材料内容选择最佳答案，并将其标号填入题前括号内。

　　1.Howmuchdoestheglassweigh?

　　A.50grams.B.100grams.

　　C.125grams.D.Wedon'tknow.

　　2.Whydidtheprofessorholdtheglass?

　　A.Becausehewantedtoshowlifewasalwayshard.

　　B.Becausehewantedtooffersomedrinkstoothers.

　　C.Becausehewantedtoknowtheweightoftheglass.

　　D.Becausehewantedtoexplainsomethingaboutlife.

　　3.Whichofthefollowingistrue?

　　A.Theprofessorwantedtoshowthestudentshowheavytheglasswas.

　　B.Theweightoftheglasswouldchangeifyouhelditlonger.

　　C.Theglassitselfmadethearmacheandthemusclestress.

　　D.Theprofessor'sarmwouldacheifheheldtheglassforalon