Welcometotheunit (5).doc

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1、FatigueandRest    Scientistshavemadeaninterestingexperimentaboutfatigue.    Whenamuscleinthebodyworks,itproduceslacticacid,anditisthislacticthatmakesthemuscletired.    Fatigueisnotjustachemicalprocess(过程),itisalsoabiologicalprocess.Wecan’tjust"remove"fatigue；wemustal

2、lowthecellsofthebodytorest.Damagesmustberepaired,nervecellsofthebrainmustbe"recharged,"thejointsofthebodymustreplaceuseduplubricants.Sleepwillalwaysbenecessaryasawayofrestoringthebody’senergyafterfatigue.    However,apersonwhohasbeenworkinghardathisdeskforhoursmaynot

3、wanttoliedownatallwhenheistired.He’drathertakeawalk!Orwhenchildrencomehomefromschooltheywanttorunouttoplaynottoliedownandrest.    Thereasonisthatifonlyacertainpartofthebodyistriedthebestwaytomakethatpartfeelfreshagainistomakeotherpartsofthebodyactive!Wecanactuallyres

4、tbymeansofactivity.Ofcourse,ifyouaretotallyexhausted,thebestthingtodoistogotosleep!第1页共1页