Ateacherbeganhisclassbyholdingupaglasswithsomewaterinit.Hehelditupforalltoseeandaskedthestudents"Howmuchdoyouthinkthisglassweighs?""50g!""100g!""125g!"the

　　Ateacherbeganhisclassbyholdingupaglasswithsomewaterinit. Hehelditupforalltoseeandaskedthestudents"Howmuchdoyouthinkthisglassweighs?"

　　"50g!""100g!""125g!"thestudentsanswered.

　　"Ireallydon'tknowunlessIweighit"saidtheteacher"butmyquestioniswhatwouldhappenifIheldituplikethisforafewminutes?"

　　"Nothing!"thestudentssaid.

　　"OK.WhatwouldhappenifIheldituplikethisforanhour?"theteacherasked.

　　"Yourarmwouldbegintoache"saidoneofthestudents.

　　"You'reright. NowwhatwouldhappenifIhelditforaday?"

　　"Yourarmcouldgonumb.Havetogotohospitalforsure!"saidanotherstudent.Allthestudentslaughed.

　　"Verygood.Butduringallthisdidtheweightoftheglasschange?"askedtheteacher.

　　"No."thestudentssaid.

　　"Thenwhatcausedthearmacheandthemuscle(肌肉)stress?"

　　Thestudentsfellsilentforamoment.

　　"Puttheglassdown!"saidoneofthestudents.

　　"Exactly!"saidtheteacher."Theproblemsoflifearesomethinglikethis.HoldthemforafewminutesinyourheadanditseemsOK.Thinkofthemforalongtimeandtheybegintomakeyouache.Holdthemevenlongerandyouwillnotbeabletodoanything.It'simportanttothinkofthe challenges(挑战) inyourlifebutit'sevenmoreimportanttoputthemdownattheendofeverydaybeforeyougotosleep.Thatwayyouarenotstressed.Youwakeupfreshandstrongandcandealwithanychallengethatcomesyourway!"

　　Remembertoputtheglassdowntoday.

　　1.Howmuchdoyouthinkthisglasswhichwasheldbytheteacherweighs?

　　A.50g B.125g C.Idon’tknow. D.100g

　　2.Whatwouldhappeniftheteacherheldtheglassuplikethisforanhour?

　　A.Oneofthestudentsthoughthisarmcouldgonumb.

　　B.Oneofthestudentsthoughthisarmwouldbegintoache.

　　C.Oneofthestudentsthoughthisarmwouldbechanged.

　　D.Oneofthestudentsthoughthisarmwouldbelost.

　　3.Whydidtheteacherholdupagla