Lisawasrunninglate．Lisa,25,hadalottodoatwork,plusvisitorsontheway:herparentswerecominginforThanksgivingfromherhometown．Butasshehurrieddownthesubwaystairs,shestartedtofeeluncomfortablywarn．Bythetimeshegottotheplatform,Lisafeltweakandtired--maybeithadn'tbeenagoodideatogivebloodthenightbefore,shethought．Sherestedherselfagainstapostclosetothetracks. Severalyardsaway,Frank,43,andhisgirlfriend,Jennifer,foundaspotclosetowherethefrontofthetrainwouldstop．Theyweredeepindiscussionaboutahousetheywerethinkingofbuying. Butwhenheheardthescream,followedbysomeoneyelling,"Oh,myGod,shefellin!"Frankdidn'thesitate．Hejumpeddowntothetracksandransome40feettowardthebodylyingontherails．"No!Notyou!"hisgirlfriendscreamedafterhim. Shewasrighttobealarmed．BythetimeFrankreachedLisa,hecouldfeelthetracksshakingandseethelightcoming．Thetrainwasabout20secondsfromthestation. Itwashardtolifther．Shewasjustout．Buthemanagedtoraiseherthefourfeettotheplatformsothatbystanderscouldholdherbythegrinsanddragherawayfromtheedge．ThatwaswhereLisabrieflyregainedconsciousness,feltherselfbeingpulledalongtheground,andsawsomeoneelseholdingherpurse. Lisathoughtshe'dbeenrobbed．Awomanheldherhandandamangavehisshirttohelpstopthebloodpouringfromherhead．Andshetriedtotalkbutshecouldn't,andthatwaswhensherealizedhowmuchpainshewasin. Policeandfireofficialssoonarrived,andFranktoldthestorytoanofficer．Jennifersaidherboyfriendwascalmontheir40-minutetrainridedowntown--justashehadbeensecondsaftertherescue,whichmadeherthinkaboutherreactionatthetime."IsawthetraincomingandIwasthinkinghewasgoingtodie．"sheexplained. WhatwasthemostprobablecauseforLisa'sweakness?
A.She had run a long way. B.She felt hot in the subway. C.She had done a lot of work. D.She had donated blood the night before.正确答案D
