题目

一束几种不同的正离子，垂直射入有正交的匀强磁场和匀强电场区域里，离子束保持原运动方向未发生偏转．接着进入另一匀强磁场，发现这些离子分成几束如图．对这些离子，可得出结论 A．它们的动能一定各不相同 B．它们的电量一定相同 C．它们的质量一定各不相同 D．它们的比荷一定各不相同 答案：DI did very badly at school. My headmaster thought I was 1 and when I was 14 years old, he predicted, “You are never to be 2 but a failure.” After 5 years of poor jobs, I fell in love with a very nice middle-class girl. It was the best thing 3 could have happened to me. I 4 I should do something positive with my life because I wanted to prove 5 her that what people said about me had gone 6, especially her mother, who once said to me, “Let’s 7 it. You’ve failed every thing you’ve ever done.” So I tried hard with my 8 and went to 9. My first novel 10 while I was still a college student. After college, I taught during the day in high schools and attended 11 classes at London University, where I 12 a degree in history. I became a lecturer at a college and was thinking of 13 that job to write full time when I was 14 a part-time job at Leeds University. I began to feel proud of myself---here was a working-class boy who’d 15 school early, now teaching at the university. My writing career 16 when I discovered my own writing 17. Now I’m rich and famous, have been on TV, and met lots of film stars. 18 what does it mean? I just wish that all those people who have 19 me down had just said, “I believe in you and you will be 20.”1.A.naughtyB.lazyC.uselessD.raggy2.A.nothingB.somethingC.everythingD.anything3.A.whenB.thatC.whichD.as4.A.thoughtB.promisedC.decidedD.expected5.A.toB.forC.withD.at6.A.ridiculousB.acceptableC.believableD.wrong7.A.seeB.faceC.treatD.react8.A.writingB.experimentC.practiceD.composition9.A.schoolB.collegeC.clubD.company10.A.went acrossB.put asideC.came outD.set off11.A.lectureB.writingC.teachingD.evening12.A.receivedB.acceptedC.gaveD.offered13.A.giving upB.paying forC.signing upD.ridding of14.A.paidB.madeC.offeredD.tried15.A.finishedB.goneC.delayedD.left16.A.made offB.took offC.gave offD.moved off17.A.styleB.habitC.ideaD.skill18.A.ThereforeB.ButC.ThoughD.For19.A.writtenB.turnedC.tornD.put20.A.cheerfulB.enjoyableC.successfulD.forgettable