[单选题]在直角△ABC中,CD是斜边AB上的高,则下列等式不成立的是A.B.C.D.
[单选题]Can you tell me ___ which you based your calculation __ detail ?A.on; inB.on; atC.about ;inD.about; for
[单选题]___________, the northerners are fond of dumplings while the southerners are fond of rice.A.In commonB.In totalC.In generalD.In particular
[单选题]She went to the bookstore and bought________.A. dozen book B. dozens booksC. dozen of books D. dozens of books
[单选题]—Why did you go back to the shop—I left my friend_______ there.A.waitingB.to waitC.waitD.waits
[单选题]“1x19成等比数列”是“”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p:|x|<1,命题q:x2+x-6<0,则是成立的( )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]---It is not a secret that CEOs of major companies earn a large amount each year.--- I agree. ____ the hard economic times, it seems that their salaries have remained the same.A.Apart fromB.Thanks toC.Regardless ofD.In regard to
[计算题]如图,三定点A(2,1),B(0,-1),C(-2,1);三动点D,E,M满足,,,t∈[0,1].(1)求动直线DE斜率的变化范围; (2)求动点M的轨迹方程.
[单选题]向量、的夹角为60°,且a,2,则2a-5等于( )A.1B.C.2D.4
[单选题]The energy Jenny Bowen has devoted in the past ten years________the orphans has been considered________of great value.[ ]A.to help;beingB.to helping;to beC.to help;to beD.helping;being
[单选题]命题“存在一个三角形,内角和不等于180°”的否定为[ ]A.存在一个三角形,内角和等于180°B.所有三角形,内角和都等于180°C.所有三角形,内角和都不等于180°D.很多三角形,内角和不等于180°
[单选题]命题“x>0,都有x2-x≤0”的否定( )A.x<0,都有x2-x>0B.x>0,都有x2-x>0C.彐x>0,使得x2-x>0D.彐x≤0,使得x2-x>0
[单选题]____the Spring Festival in China, people may give children pocket money _____red paper.[ ]A. In; atB. In; with C. At; inD. At; on
[单选题]“How could you treat me like that?” John asked his wife, eyeing her angrily from _______ the kitchen table.A.atB.acrossC.throughD.on
[单选题]Some students often listen to music ___ ___ classes to refresh themselves.[ ]A. betweenB. among C. overD. during
[单选题]Helen always helps her mother do the housework even though going to school ________ most of her day. A.takes upB.makes upC.saves upD.uses up
[单选题]命题p:x∈R且满足sin 2x=1.命题q:x∈R且满足tan x=1.则p是的( )A.充分非必要条件B.必要非充分条件C.充要条件D.既不充分也不必要条件
[单选题]“a=1”是“函数f(x)=lg(ax+1)在(0,+∞)单调递增”的[ ]A.充分必要条件B.必要不充分条件C.充分不必要条件D.既不充分也不必要条件
[单选题]The success of a government should be measured ________ the happiness of the people as well as the development of economy.[ ]A. in face ofB. in place ofC. in terms ofD. in honour of
[单选题]f( ).g(x)是定义在R上的函数,h(x)=f(x)+g(x)则“f( ).g(x)均为偶函数”是“h(x)为偶函数”的( )A.充要条件 B.充分而不必要条件C.必要而不充分条件D.既不充分也不必要条件