Whatareyoudoingrightnow?Yesyouarereadingthispage.Thatalsomeansyou'removingyour

eyes.You'rethinking.You'rebreathing.You'relistening.Possiblyyou'reshifting(变换)positions.You're

alsofeelingthings—thisbookyourchairemotions.Whatletsyoudoallthesethingsatthesametime?

Yourbrain.

Yourbrainisthecontrolcenterofyourbodyandmind.Withoutyourbrainyoucan'tdoanything.Yourbrainhasmorethan100billionnerve(神经)cells.Eachnervecellmakesfrom1000to10000

connectionswithothernervecells.Thenervecellssendimpulsesbackandforthinyourbrainandtoand

fromeverypartofyourbody.Afteryoureachtheageof20thoughyourbraincellsstarttodie.Thisis

common.Howeverifyousufferanillnessorinjuryevenmorenervecellsdieinyourbrain.Whena

nervecelldiesthethousandsofconnectionsitmadewithothernervecellsarelost.

Untilrecentlyscientistsbelievedthatthebraindidnotreplaceitsdeadcells.Newstudieshowever

provenot.Scientistshavefoundnewnervecellsinapartofthebraincalledthehippocampus(海马区).

Thehippocampushelpsthebrainformmemoriesfromnewexperiences.

Thediscoveryofthesenewnervecellsisnotacureforanythingyet.Itgiveshopehoweverofacure

forbraindamagefromsuchthingsasepilepsy(癫痫病)LouGehrig'sdiseasecaraccidentsandstrokes.Somedayscientistsmightbeabletousethenewcellstoreplacedamagedbraincells.Suchacure

howevermaytakeabouttenyearstodevelop.Soatthesametimeuseyourhead—protectit!

2. Nervecellsinthebrain______.

A.sendmassagestoeverypartofthebody

B.makeconnectionsonlytoothercellsinthebrain

C.cancureLouGehrig'sdisease

D.areaperson'smemory

2.Thelastsentenceofthepassagesuggeststhatpeople______.

A.shouldusetheirheadbycarefullythinkingthroughsituations

B.shouldbecarefulnottoinjuretheirbrains

C.haveaskull(头盖骨)thatprovidesalltheprotectionneededbythebrain

D.wouldseeaquickcureforbraindisease

3.Theauthorexplainswhatthehip