[单选题]设=(1,),=(0,1)为坐标原点,动点P(x,y)满足0≤≤1,0≤≤1,则z=y-x的最大值是( )A.-1 B. 1 C.-2 D.
[单选题]—Listen,there is some strange noise.This machine must be________.—I think so.You must have it checked.[ ]A. out of orderB. out of dateC. out of sight D. out of control
[单选题]When you visit a museum you must ask for _____ before taking photographs inside it.?A.promiseB.permissionC.considerationD.support
[单选题]已知向量=(4,x),=(-4,4),若、平行,则x的值为[ ]A.0 B.-4 C.4 D.x=±4
[单选题]His diet can not be considered as healthy because it contains a lot of fat ________ meat, cakesAnd cream.[ ]A.in the possession ofB.in the form ofC.in the charge ofD.in the name of
[单选题]设{an}是等比数列,则“a1<a2<a3”是“数列{an}是递增数列”的[ ]A.充分而不必要条件 B.必要而不充分条件 C.充分必要条件 D.既不充分也不必要条件
[单选题]集合A={x||x|≤4,x∈R},B={x|(x+5)(x-a)≤0},则“AíB”是“a>4”的A.充分不必要条件B.必要不充分条件C.充要条件D.既不充分也不必要条件
[单选题]命题“所有能被2整除的整数都是偶数”的否定是[ ]A.所有不能被2整除的整数都是偶数B.所有能被2整除的整数都不是偶数C.存在一个不能被2整除的整数都是偶数D.存在一个能被2整除的整数不是偶数
[单选题]They have been ____________their neighbours, that is to say, they get along well with their neighbours. [ ]A. on good term B. on bad term C. on good termsD. on bad terms
[单选题]They are similar___appearance, but differ_characterA.to; fromB.in; fromC.to; inD.in; in
[单选题]-Was it in A.ril, 1970 ________ China succeeded ________ sending its first satellite into space-Yes, thats right.[ ]A. when; inB. that; onC. which; onD. that; in
[单选题]已知a∈R,且a≠0,则<1是“a>1”的( ).A.充分非必要条件B.必要非充分条件C.充要条件D.既非充分又非必要条件
[单选题]When Steven suddenly remembered that he had left his mobile in the office, the train was already________.[ ]A. on the goB. on the riseC. on the run D. on the move
[单选题]—How is your plan getting along—I can’t carry on ________ any longer.Someone must help me.A.singleB.simplyC.aloneD.lonely
[单选题]It was Sarahs sister who she had great respect for that tricked her ________ carrying drugs. [ ]A. in B. toC. into D. from
[单选题]It can’t be a(n) __________that another big fire broke out in the same restaurant in three months.A.accidentB.incidentC.chanceD.coincidence
[单选题]A professor said the rise of the BRICS countries(金砖国家) is a/an _______ of the end of the world in the control of the USA.A. barrier B. process C. aspect D. symptom
[计算题]设命题p:函数f(x)=lg(ax2的定义域为R,命题q:不等式2x+1-1<ax,对一切正实数x恒成立,如果“p或q”为真,“p且q”为假;求实数a的取值范围.
[单选题]Most Chinese carmakers are years behind their western counterparts _______ quality, technology and service.A.in terms ofB.in need ofC.in favor ofD.in praise of
[单选题]一Mae Whitmans mother is a voice-artist and her father builds sets on stage. ――__she ended up in acting.A.There is no doubtB.It is no surpriseC.There is no pointD.It is no use
[单选题]已知m,n是不同的直线,α,β是不同的平面,则“n⊥α”的一个充分不必要条件是[ ]A.α∥β,n⊥βB.α⊥β,nβ C.α⊥β,n∥β D.m∥α,n⊥m