InhighschoolIjoinedthegirlathleticclub.AtourfirsttrackmeetIenteredforthelongjumpbutwasmadeanalternate（替补）forthe50yarddash.Ididn’tlikeitsinceIwasbetteratlongdistancebuttheyassuredmeIwouldneverhavetorun;theyjustranoutofalternate.AsIwalkeduptothestartlineIsawmyDadonthesidelines.Hewaswatching.Positionreadysetandoffwentthestartinggun.BelieveitornotIclosedmyeyesandranlikeI’dneverrunbefore.IknewIdidn’thaveachanceofwinning.ButIstartedtohearcheeringandthoughtforaminutewasitpossible?IopenedmyeyesandtomydisappointmenteveryoneelsewascrossingthefinishlineinchesawayfromeachotherandIwasonlyhalfthedistance.Thatmomentfeltlikedays.Ifeltsostupid.Ijustwantedtomeltintothegroundanddisappeared.WorsethanthatmyDadwaswatchingandthenIfeltashamed.IkeptrunninghardasIcouldcryingallthewaytowardsthefinishline.ItseemednoonenoticedmeasIcrossedthefinishline.IsawmyDadstandingtherelookingatme.Iwasashamedtolookathim.Hewalkedovertomeandsaid“I’msoproudofyou.”Iwassurprised“Forwhat?EveryoneelsefinishedbeforeIevengothalfway.Ilookedlikeafool.”“Becauseyoudidn’tgiveupnotevenwhenyourealizedwhathadhappened.Yougaveityourallandfinished.”Ilaughedandcriedatthesametime.IfindIcanfacewhatseemsimpossibleevenaloneandafraidandthatwinningdoesnotalwayscomeinasyouexpect.IgivemybestefforttoallIdowinorlose.Idon’tgiveupinthemiddleofanything.Theauthormeanttocompetein.A.the50yarddashB.thelongjumpC.thelong-distancerunD.thehighjumpWhentheauthorheardcheeringshethought.A.shehadthechancetowinthegameB.sheleftothersinchesawayhalfwayC.othercompetitorswereencouragingherD.somebodyhadwonthegameWhathappenedaftertheauthorcrossedthefinishline?A.Shecriedatthesightofherfather.B.Everyonecheeredherforhersuccess.C.Herfarthercameupandcomfortedher.D.Shefeltashamedtomeetherclassmates.Whatlessoncanwelearnformtheauthor’sexperience?A.Whatseemsimpossiblealwaysbecomespossible.B.Don’tlosehearthalfwaywhateveryoudo.C.Successwillcomeaslongasyouexpectit.D.Trytodoeverythinguntilyouwinintheend.

20A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、120、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、130、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、140、A、B、C、D、A

设A={a,b,c,{a,c}},B={a,c,d},则B-A=____,A⊕B=____。 A: {a,c,d}, {{a,c},b,d} B: {d}, {a,c,b,d} C: {d}, {{a,c},b,d} D: {d}, {a,c}

以下集合A={a,b,c,d}上关系，其中（ ）是等价关系。 A: {(a,a),(a,d),(b,b),(b,c),(c,b),(c,c),(d,a) } B: {(a,a),(a,b),(b,a),(b,b),(c,c),(c,d),(d,c),(d,d)} C: {(a,a),(b,b),(b,c),(c,b),(c,c),(d,a),(d,d)} D: {(a,a),(a,b),(b,a),(b,b),(b,c),(c,b),(c,c),(d,d)}

A: A＞B＞C＞D B: D＞C＞B＞A C: D＞B＞A＞C D: C＞A＞B＞D

三目运算符表达式“d=a＞b(a＞ca:c):(b＞cb:c)；”等价于下列①、②、③、④四组程序的（）组解释 ①if(a＞b)d=b; else if(a＞c) d=c; else if(b＞c) d=c; else d=b; ②if(a＞b){ if(a＞c)d=a; else d=c; } else { if(b＞c) d=b; else d=c;} ③if(a＞b) if(a＞c) d=c; else d=a; else if(b＞c) d=c; else d=b; ④if(a＞b) d=a; else if(a＞c) d=a; else if(b＞c) d=b; else d=c; A: ① B: ② C: ③ D: ④

D A C C D 6-10 A C D D C 11-15 A: C C B: 16-20 C: C C B B

F={A→C，C→A，B→AC，D→AC，B D→A}，则F的最小依赖集是 A: {A→C，B→C，C→A，B D→A} B: {A→C，C→A，D→C，D→A} C: {A→C，C→A，B→A，B→C} D: {A→C，C→A，B→C，D→C}

A、B、C、D为任意集合，以下正确的是 A: (A∪B)´(C∪D) = (A´C)∪(B´D) B: (A-B)´(C-D) = (A´C)-(B´D) C: (A∩B)´(C∩D) = (A´C)∩(B´D) D: (AÅB)´(CÅD) = (A´C) Å (B´D)

设V=a，b，c，d，则与V能构成强连通图的边集合是 (51) 。 A: A) E=＜A，d＞，＜b，a＞，＜b，d＞，＜c，b＞，＜d，c＞ B: B) E=＜a，d＞，＜b，a＞，＜b，c＞，＜b，d＞，＜d，c＞ C: C) E=＜a，c＞，＜b，a＞，＜b，c＞，＜d，a＞，＜d，c＞ D: D) E=＜a，b＞；＜a，c＞，＜a，d＞，＜b，d＞，＜c，d＞