Doyoueverdohomeworkwhilelisteningtomusic，orwatchTVwhiletextingfriend？Itmayseemlikeanobviousquestionsincemostofusmultitask（做多个任务） allthetime．

ButaccordingtoarecentstudypublishedinthejournalPLOSONE，using anumberofmediadevices（媒体设备） atthesametmecouldbechangingourbrains．

ThereportwascarriedoutbySussexUniversityintheUK．Researchersfirstasked75adultsabouthowoftentheyspenttimemultitaskingbetweendifferentkindsofmedia．ThentheycheckedtheibrainswithanMRImachine．Thosewhoreportedheaviermediamultitaskinghadlessgraymatterintheirbrains．Graymatteristhepartofthebrainthathelpstodealwithinformationandcontrolemotions（情感）．

Soismultitaskingreally rotting ourbrainsandmakingusstupid？Wecan'tbesure，accordingtoresearchers．

Theysaythattheresultsonlyshowalink．Theyareunsurewhethermultitaskingreducesgraymatterorifpeoplewithlessgraymatteraresimplymorelikelytomultitask．

"Mediamultitaskingisbecomingmorepopularinourlivestodayandthereisincreasingconcernaboutitsinfluence（影响） onourwell-being，"saidBritishscientistKepKeeLoh，whodirectedthestudy．

Lohsaysthatmorestudyisneededtosupporttheideathatourbehaviorsarechangingourbrains．Butifit'strue，itcouldsupportearlierstudiesaboutmediamultitasking．

In2012，astudybyMichiganStateUniversityintheUSfoundthatpeopleusingseveralmediadevicesatthesametimeweremorelikelytobeanxiousordepressed．

Itseemsthatmoreresearchintotheissueisneeded．Butnomatterwhat，youshouldconsiderliiting（限制） yourselftoonescreenatatime，theHuffingtonPostreported．

Foronething，Multitaskingdoesn'tactuallyworkifyouaretryingtobemoreefficient（有效率的）．You'regoingfromoneactiontoanotherinsteadoftrulydoingtwothingsatatime．Itwastesyourenergyandslowsyoudown．And onceyou'vesloweddown，itcanbehardtopickbackupwhereyouleftoff．

Ifyouwanttofinishalistofjobs，"setgoals，establisharoutine（常规），andtakeregularbreaks"，suggestedTheHufingtonPost．

21．WhatdidtherecentstudybySussexUniversityfind？___

A．Mostpeopl