问题
不定项选择
水平弹簧振子做简谐运动,轨迹上有A、B两点,已知振子位于A、B两点的动能EA<EB,且A、B两点的位移方向相同.关于振子通过A、B两点的加速度aA、aB和速度vA、vB一定有[ ]
A.aA>aB,且方向相同
B.aA<aB,且方向相反
C.vA>vB,且方向相同
D.vA<vB,且方向相同
答案
答案:A
水平弹簧振子做简谐运动,轨迹上有A、B两点,已知振子位于A、B两点的动能EA<EB,且A、B两点的位移方向相同.关于振子通过A、B两点的加速度aA、aB和速度vA、vB一定有[ ]
A.aA>aB,且方向相同
B.aA<aB,且方向相反
C.vA>vB,且方向相同
D.vA<vB,且方向相同
答案:A
根据短文内容,从下框的A-F选项中选出能概括每一段主题的最佳选项。选项中有一项为多余项。 | |
| |
1.______ The biggest problem most people face in learning a new language is their own fear. They worry that they won't say things correctly or that they will look stupid so they don't talk at all. Don't do this. The fastest way to learn anything is to do it - again and again until you get it right. Like anything else, learning English requires practice. Don't let a little fear stop you from getting what you want. 2.______ Even if you study English at a language school it doesn't mean you can't learn outside of class. Using many different sources, methods and tools as possible, will allow you to learn faster. There are many different ways you can improve your English, so don't limit yourself to only one or two. The internet is a fantastic resource for virtually anything, but for the language learner it's perfect. 3.______ The absolute best way to learn English is to put yourself in it. Take notes in English, put English books around your room, listen to English language radio broadcasts, watch English news, movies and television. Speak English with your friends whenever you can. The more English materials that you have around you, the faster you will learn and the more likely it is that you will begin "thinking in English". 4.______ This is not only a fun way to learn but it is also very effective. By watching English movies (especially those with English subtitles) you can expand your vocabulary and hear the flow of speech from the actors. If you listen to the news you can also hear different accents. 5.______ Another very effective method of learning English is singing. In fact, it is often used as a way of improving comprehension. The best way to learn is to get the lyrics (words) to the songs you are listening to and try to read them as the artist sings. There are several good internet sites where one can find the words for most songs. In this way you can practise your listening and reading at the same time. |