PALOAITOCalifornia—“Switchingoffthetelevisionmayhelppreventchildrenfromgettingfatter—eveniftheydonotchangetheirdietorincreasetheamounttheyexercise”USresearcherssaidlastweek.

Astudyof192thirdandfourthgradesgenerallyagedeightandninefoundthatchildrenwhocutthenumberofhoursspentwatchingtelevisiongainednearlytwopounds(0.91kg)lessoveraone-yearperiodthanthosewhodidnotchangetheirtelevisiondiet.

“Thefindingsareimportantbecausetheyshowthatweightlosscanonlybetheresultofareductionintelevisionviewingandnotanyotheractivity”saidThomasRobinsonapediatrician(儿科专家)atStanfordUniversity.

“Americanchildrenspendanaverageofmorethanfourhoursperdaywatchingtelevisionandvideosorplayinggamesandratesofchildhoodbeingveryfathavedoubledoverthepast20years”Robinsonsaid.

InthestudypresentedthisweektothePediatricAcademicSocieties’annualmeetinginSanFranciscotheresearcherspersuadedabout100ofthestudentstoreducetheirtelevisionviewingbyone-quartertoone-third.

Childrenwatchingfewerhoursoftelevisionshowedasignificantlysmallerincreaseinwaistsizeandhadlessbodyfatthanotherstudentswhocontinuetheirnormaltelevisionviewingeventhoughneithergroupateaspecialdietnortookpartinanyextraexercise.

“Oneexplanationfortheweightlosscouldbethechildrenunstucktothetelevisionmaysimplyhavebeenmovingaroundandburningoffcalories”Robinsonsaid.

“Anotherreasonmightbeduetoeatingfewermealsinfrontofthetelevision.SomestudieshavesuggestedthateatinginfrontoftheTVencouragespeopletoeatmore”Robinsonadded.

56.Thepurposeofthefirsttwoparagraphsis______.

A.toreportthetimechildrenspendwatchingTV

B.toshowthatmoreTVtimeleadstogettingfatter

C.totellusthebestwaytoreduceweight

D.tointroducethebackgroundoftheresearch

57.AccordingtothepassagethetimeAmericanchildrenusuallyspendonwatchingTV____.

A.ismorethanfourhoursaday B.islessthanfourhoursaday

C.doubledinthelasttwentyyears D.ismorethanonanyotheractivities