[单选题]若,,均为单位向量,且,,则的最大值为( )A.-1B.1C.D.2
[计算题](本小题满分12分)已知4,4,(2a-3b)·(2a+b)=61(1)求a+b和ab.(2)若Ab=a.Ac=b,作△ABC,求△ABC的面积
[单选题]Whitney Houston’s sudden death suggests that drug abuse is such a serious problem ______ we shoulddeal with properly.?[ ]A. asB. thatC. whichD. where
[单选题]—What’s your plan for the future—I hope to get a job in the local newspaper at first and ______ work for China Daily.A.regularlyB.frequentlyC.eventuallyD.gradually
[单选题]Most of the evidence was destroyed in the fire. ______, it would be almost impossible to prove Jim guilty.A.AnyhowB.ThusC.HoweverD.Besides
[单选题]More and more high-rise buildings have been built in big cities ____ space.[ ]A.in search ofB.in place of C. for lack of D. for fear of
[单选题]She says that shell have to close the shop ________ business improves.A.ifB.unlessC.afterD.when
[单选题]_______ we often have different opinions on studying, we are good friends. [ ]A. As long as B. Now that C. Even though D. In case
[单选题]I remember everything ______it had happened yesterday.A.in caseB.even ifC.as long asD.as if
[单选题]We really enjoyed Disneyland. We took all the rides, some of ________ twice, and had lots of fun. I felt just like a kid again.A.whichB.thatC.itD.them
[单选题]Yesterday he called ____me ____my office and told me the good news.[ ]A. at, at B. on,onC. at,onD. on ,at
[单选题]The workers are so _____ to the noise of the machine that they dont even notice it during their work. [ ]A. accustomedB. subjective C. familiarD. associated
[单选题]As we have known from the map of the world,this is ________.A.twice as large an island as that B.twice as larger as that islandC.as twice large as that oneD.twice as a large island as that
[单选题]I had just stepped out of the bathroom and was busy drying myself with a towel ______ I heard the steps.A. while B. whenC. sinceD. after
[单选题]—What on earth do you want—I just want a common sports coat-nothing ________.[ ]A. fancyB. amazingC. informalD. valuable
[单选题]I can’t say I’m the best. I have only ______ made more efforts than others.A.definitelyB.relativelyC.obviouslyD.certainly
[单选题]It is known to all that _____ you exercise regularly, you wont keep good health.A. unless B. wheneverC. although D. if
[单选题]Compared with his sister, Jerry is even more _____ to, and more easily troubled by, emotional and relationship problems.( )A. sceptical B. addictedC. available D. sensitive
[单选题]Fred entered without knocking and,very out of breath, sank____ a chair. [ ]A. on B. off C. into D. to
[单选题]— What do you think of your English teachers work— Its ______ all praise. ( )A. for B. over C. beyondD. with
[单选题]If you want to book tickets for a film in Qionghai, just call 62838009. It _______be simpler.A.mustnt B.wontC.neednt D.cant