[单选题]已知=(3,4),=(5,12),则与夹角的余弦为A、B、C、D、
[单选题]Nearly three months had gone by ______ the seriously injured girl showed a slight sign of recovery.A.untilB.afterC.since D.before
[单选题]Once people have seen something actually happens, they are much more_______to accept the change.A.likelyB.possibleC.unlikelyD.probably
[单选题]The tiger, once a animal to humans, is now ?of disappearing on the earth.A.dangerous, dangerB.dangerous, in dangerC.in danger, in dangerD.danger, in danger
[计算题](本题9分)在平面直角坐标系中,点、、.(1)求以线段为邻边的平行四边形两条对角线的长;(2)当为何值时,与垂直;(3)当为何值时,与平行,平行时它们是同向还是反向.
[单选题]Please take down my telephone number ________ something important happens.A.in caseB.now thatC.even thoughD.as if
[单选题]To understand the grammar of the sentence, you must break it _____?into parts. ( )A. down B. up C. off D. out
[计算题]△ABC中,过BC边的中点D作BC边的垂线,P是上不同于D的任一点. 记 AB=aAC=b. 若a6,4.求AP. CB的值
[单选题]△ABC中,若AD=2DB,CD=-CA+2CB,则=( )A.B.C.D.
[单选题]设向量a,b均为单位向量,且(a+b)2=1,则a与b的夹角为A.B.C.D.
[单选题]A.l the people _____?at the party are fond of the music of the TV play.[ ]A. presentB. interestedC. importantD. thankful
[单选题]Your story is perfect ; I’ve never heard ___before.A.the better oneB.the best oneC.a better oneD.a good one
[单选题]与向量a=(1,-1,-2)垂直的一个向量的坐标是[ ]A.(,1,1)B.(-1,-3,2)C.D.
[单选题]They set sail from Iceland ______ the party.[ ]A. to searchB. in search forC. in search ofD. to research for
[单选题]The meeting is beginning at 8 o’clock. _____, let’s make some preparations for it.A.WhenB.MeanwhileC.WhileD.During
[单选题]When you study the local map, youll find this town is ________ [ ]A.twice as a large town as thatB.twice the size of that oneC.twice as larger as that oneD.twice as larger a town as that
[单选题]----- Do you need any help, Lucy----- Yes. The job is ________ I could do myself.[ ]A. less than B. more than C. no more thanD. not more than
[单选题]Seen from the top, the stadium looks just like a bird’s nestof tree branches.A.to makeB.madeC.makingD.being made
[单选题]It?seems?that?living?green?is?________?easy?and?affordable.?A.small?step?makes?a?big?difference. [ ]A. exactlyB. fortunatelyC. surprisinglyD. hardly
[单选题]已知非零向量a、b,若a+2b与a-2b互相垂直,则[ ]A.B.4C.D.2
[单选题]Scientists are convinced _____ the positive effect of laughter _____ physical and mental health.( )A. of; at B. by; inC. of; on D. on; at