Duringthe19thcenturyscientistsfoundthatwhencertainpartsofthebrainofapersonwerehurthewouldlosethepowerofdoingcertainthings.Andsopeoplethoughtthateachpartofthebraindoesadifferentjob.Butmodernresearc

　　Duringthe19thcenturyscientistsfoundthatwhencertainpartsofthebrainofapersonwerehurthewouldlosethepowerofdoingcertainthings.Andsopeoplethoughtthateachpartofthebraindoesadifferentjob.Butmodernresearchhasdiscoveredthatthisisnotsoforitisnoteasytoshowexactlywhateachpartofthebraindoes.

　　Inthepastfiftyyearstherehasbeenagreatincreaseintheamountorresearchdoneonthebrain.Scientistshavefoundoutthatthewaythebrainworksisnotsosimpleaspeopleingeneralmaythink.Chemiststellusthatabout100000chemicalchangestakeplaceinthebraineverysecond.Somerecentresearchesalsosuggestthatwecanremembereverythingthathappenedtous.Wemaynotbeabletothinkofthethingswehaveheardandseenbutitiskeptthereinthestore-houseofthehumanmind.Earlierscientiststhoughtthatthepowerofone’sbraingotweakerandweakerasonegrowsolder.Butitisplentyofexerciseitkeepsitspower.Itisnowthoughtthatisnottrue.Aslongasthebrainisgivenplentyofexerciseitkeepsitspower.Ithasprovedthatanoldpersonwhohasalwaysbeenactiveinthemindhasaquickermindthanayoungpersonwhohasdonephysicalworkwithoutusingmuchofhisbrain.

　　小题1:Inthelastcenturyscientistsfoundthatapersonwouldlosethepowertodocertainthings_____.A．whenhegotweakerinhealthB．ifcertainpartsofhisbrainwerehurtC．afterhedidaquitedifferentjobD．whenhegrewolder小题2:Scientiststodayarestillunabletoshowexactly______.A．whateachpartofthebrainisdoingB．howmanychemicalchangestakeplaceinthebraineachsecondC．whethereachpartofthebraindoesthesamejobD．whichpartofthebrainisthemostimportant小题3:Ithasbeenfoundthatone’sbrainusuallyworks______.A．fasterwhenheisoldB．alittlenowandalittlethenC．inaverysimplewayD．withoutanyrestalldaylong小题4:WhichofthefollowingisNOTtrueaccordingtothetext?A．Scientistsareworkinghardattheresearcheson