| 如图所示，轻质弹簧的一端与固定的竖直板P拴接，另一端与物体A相连，物体A置于光滑水平桌面上，A右端连接一细线，细线绕过光滑的定滑轮与物体B相连．开始时托住B，让A处于静止且细线恰好伸直，然后由静止释放B，直至B获得最大速度．下列有关该过程的分析中正确的是（ ） A．B物体受到细线的拉力保持不变 B．B物体机械能的减少量大于弹簧弹性势能的增加量 C．A物体动能的增量等于B物体重力对B做的功与弹簧弹力对A做的功之和 D．A物体与弹簧所组成的系统机械能的增加量等于细线拉力对A做的功 |
BD
I truly hope that at the end of this short essay(短文) you will know how to learn English. I was born in Somalia, and Italian is my mother tongue. 31 enough, soon after I arrived in London when I was 17, I was admitted to a sixth-form college. I found caring (体贴的) teachers there, who 32 taught me English. This, I think, was a(n) 33 factor(因素) that encouraged me to learn the language. The most important thing, 34, is to work hard. So those of you who don’t have such good teachers should not 35. When I was in London, I 36 myself to English learning as I 37 to go to university very much. Mastering the language was the only 38 to achieve my goal. Now I have 39 my master’s degree from Oxford University. Looking back, I 40 I was quite innocent (天真的),for I never imagined learning English was going to be so much 41. The more fluent I become, the 42 the language became. One can master it only 43 years of tireless efforts(努力). Some basic 44 which I would give to people who are interested in learning the language are: 1. Buy a good dictionary. 45 English learners use their dictionaries all the time. 2.46 English newspapers. Don’t forget to 47 the new words in your dictionary. 3. Listen to the radio 48 watching TV as listening to the radio helps you more. 4. Talk, talk and talk to 49 at anytime and anywhere. And even though at times it may be embarrassing(尴尬的) to make 50，you will finally correct them and remember them. Soon you will start to become fluent.
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