Theterm“multitasking”originallyreferredtoacomputer’sabilitytocarryoutseveraltasksatonetime.Formanypeople,multitaskinghasbecomeawayoflifeandevenakeytosuccess.Infact,someexcellentmentalaerobicexercises(大脑训练)involveengagingthebrainintwoormorechallengingactivitiesatatime.Althoughcheckinge-mailwhiletalkingonaphoneandreadingthenewspapermaybesecondnatureforsomepeople,manytimesmultitaskingcanmakeuslessproductive,ratherthanmore.Andstudiesshowthattoomuchmultitaskingcanleadtoincreasedstr ess,anxietyandmemoryloss.
Inordertomultitask,thebrainusesanareaknownastheprefrontalcortex(前额叶脑皮层).Brianscansofvolunteersperformingmultipletaskstogethershowthatastheyshiftfromtasktotask,thisfrontpartofthebrainactuallytakesamomentofrestbetweentasks.Youmayhaveexperiencedaprefrontalcortex“momentofrest”yourselfifyou’veeverdialed(拨电话)aphonenumberandsuddenlyforgottenwhoyoudialedwhenthelineisanswered.Whatprobablyoccurredisthatbetweenthedialingandtheanswering,yourmindshiftedtoantherthoughtortask,andthentookthat“moment”tocomeback.Researchhasalsoshownthatformanyvolunteers,jobefficiency(效率)declineswhilemultitasking,ascomparedtowhentheyperform.onlyonetaskatatime.
Multitaskingiseasiestwhenatleastoneofthetasksishabitual,orrequireslittlethought.Mostpeopledon’tfinditd ifficulttoeatandreadthenewspaperatthesametime.However,whentwoormoreattention-requiringtasksareattemptedatonetime,peoplesometimesmakemistakes.
Weoftendon’tr ememberthingsaswellwhenwe’retr yingtomanageseveraldetailsatthesametime.Withoutmentalfocus,wemaynotpayenoughattentiontonewinformationcomingin,soitnevermakesitintoourmemorystores.Thatisoneofthemainreasonsweforgetpeople’snames---evensometimesrightaftertheyhaveintr oducedthemselves.Multitaskingcanalsoaffectourrelationships.Ifsomeonecheckstheire-mailwhileonthephonewithafriend,theymaycomeoffasabsent-mindedordisinterested.Itcanalsocausethatpersontomissoroverlookkeyinformationbeingpassedontothem.
49.Whyaresomementalaerobicexercisesdesignedtoengagepeopleinmultitasking?
A.Tomakethemmoreproductive.
B.Toreducetheirstr essandanxiety.
C.Todeveloptheircommunicationskills.
D.Tohelpthemperform.dailytasksmoreeasily.
正确答案：A解析：推理判断题。根据第一段的内容可知，作者提出：“Infact,someexcellentmentalaerobicexercises(大脑训练)involveengagingthebrainintwoormorechallengingactivitiesatatime.”，之后用although引出转折，这种训练有时并不能productive。所以选择A。有部分人认为这种大脑的训练能够帮助他们高效的工作。
