请阅读短文。 AnneWhitney,asophomoreatColoradoStateUniversity,firsthadaproblemtakingtestswhenshebegancollege."Iwasalwayswellpreparedformytests.SometimesIstudiedforweeksbeforeatest.YetIwouldgointotakethetest,onlytofindIcouldnotanswerthequestionscorrectly.Iwouldblankoutbecauseofnervousnessandfear.Icouldn'tthinkoftheanswer.MylowgradesonthetestsdidnotshowwhatIknewtotheteacher."Anotherstudentinbiologyhadsimilarexperiences.Hesaid,"Myfirstchemistrytestwasverydifficult.Then,onthesecondtest,Isatdowntotakeit,andIwassonervousthatIwasshaking.Myhandsweremovingupanddownsoquicklythatitwashardtoholdmypencil.IknewthematerialandIknewtheanswers.YetIcouldn'tevenwritethemdown!" Thesetwoyoungstudentswereexperiencingsomethingcalledtestanxiety.Becauseastudentworriesandisuneasyaboutatest,hisorherminddoesnotworkaswellasitusuallydoes.Thestudentcannotwriteorthinkclearlybecauseoftheextremetensionandnervousness.Althoughpoorgradesareoftenaresultofpoorstudyhabits,sometimestestanxietycausesthelowgrades.Recently,testanxietyhasbeenrecognizedasarealproblem,notjustanexcuseorafalseexplanationoflazystudents. Specialuniversityadvisingcoursestrytohelpstudents.Inthesecourses,advisorstrytohelpstudentsbyteachingthemhowtomanagetestanxiety.Atsomeuniversities,studentstaketeststomeasuretheiranxiety.Ifthetestsshowtheiranxietyishigh,thestudentscantakeshortcoursestohelpthemdealwiththeirtensions.Thesecoursesteachstudentshowtorelaxtheirbodies.Studentsaretrainedtobecomecalminverytensesituations.Bycontrollingtheirnervousness,theycanlettheirmindsworkatease.Learnedinformationthencomesoutwithoutdifficultyonatest. AnexpertattheUniversityofCaliforniaexplains:"Withalmostallstudents,relaxationandlessstressarefeltaftertakingourprogram.Mostofthemexperiencebettercontrolduringtheirtests.Almostallhavesomeimprovement.Withsome,theimprovementisverygreat." To“blankout”isprobably__________. 查看材料
A.to be like a blanket
B.to be sure of an answer
C.to be unable to think clearly
D.to show knowledge to the teacher
正确答案是C