1、

Intoday’sworld,sleepexpertssaythatforabetternight’srest,AmericansshouldturnofftheirsmartphonesoriPadbeforesleeping.Suchelectronicproductsmakethebrainmoreactive,andtheninfluencetheirsleep.Butaccordingtoalatestsurvey,morethan90%ofAmericansregularlyuseacomputerorsomeotherkindsofelectronicproductsinthehourbeforebed.

Researchersarefindingthatman-madelightfromsomeelectronicproductsatnightmayreducethebrainchemicals(化学物质)thathelpsleep.Theresearchersshowedthatsittinginthelightfromcomputertabletsclearlyloweredlevelsofthechemicalwhichmanagesourbodyclocksandplaysaroleinthesleepcycle.

Inthestudy,theresearchersletvolunteersread,playgamesandwatchmoviesonatabletfordifferenttimewhilemeasuring(测量)howmuchlighttheireyesreceived.Theyfoundthattwohoursofsittingbeforeabrighttabletscreenatnightreducedthesleepchemicallevelsbyabout22%.

Studiesofstudentsusingcomputersatnighthavegotthesimilarresults.Andresearcherssaythatmaynotonlycausesleeplessness,butalsoraisetheriskofobesity(肥胖症),diabetes(糖尿病)andotherdiseases.

Tobeonthesafeside,theresearchersadviseustousecomputerslessbeforebed,orattheveryleastturningdownyourscreenasmuchaspossible.

【1】Whatcanwelearnfromthefirstparagraph?

A.Americansdon’tgetenoughsleep.

B.Electronicproductsareverypopular.

C.Thebrainbecomesmoreactiveatnight.

D.Sleepexpertsneverusesmartphones.

【2】ThevolunteersinthestudydidthefollowingthingsEXCEPT_____.

A.listeningtomusic

B.playingcomputergames

C.watchingmovies

D.readingelectronicbooks

【3】Theunderlinedword“that”probablymeans____inthepassage.

A.makingasurveyaboutsleep

B.usingsmartphonesinthedaytime

C.sittinginabrightroom

D.surfingtheInternetatnight

【4】Whatdoesthepassagetellustodotohaveagoodsleep?

A.LearntousesmartphonesoriPad.

B.WatchsomerelaxingTVprograms.

C.Turndownthescreentothelowest.

D.Trytosleepearlierthanbefore.