2012年6月英语试卷和答案_百度文库
两大类热门资源免费畅读
续费一年阅读会员，立省24元！
2012年6月英语试卷和答案
上传于|0|0|暂无简介
阅读已结束，如果下载本文需要使用1下载券
想免费下载本文？
定制HR最喜欢的简历
下载文档到电脑，查找使用更方便
还剩15页未读，继续阅读
定制HR最喜欢的简历
你可能喜欢您的位置：&>&&>&&>&
A Lot of Knowledge Is a Dangerous Thing
kira86 于发布 l 已有人浏览
I was looking at some polling about science over the weekend, and discovered that they helpfully pro
I was looking at some polling about science over the weekend, and discovered that they helpfully provide an online quiz consisting of the factual questions asked of the general public as part of the survey. Amusingly, one of them is actually more difficult to answer correctly if you know a lot about the field than if you only know a little. I'll reproduce it here first, if you would like to take a crack at it, and then I'll explain why it's tricky below the fold.
Choose only one answer-- this is being recorded for SCIENCE!
So, what's the problem? The correct answer is obviously &Satellites,& right?
The problem is that two of the answers are technically correct. GPS is based on a constellation of satellites sending out radio signals, but those satellites contain atomic clocks. And the atomic clocks in the satellites rely on magnets to function.
The key idea behind the atomic clock is that atoms have discrete energy states, determined by quantum physics, and move between those states by absorbing or emitting photons of light. Light, in turn, has a frequency associated with it that is determined by the energy of a single photon.
An atomic clock uses the discrete energy levels of an atom as a frequency reference. Unlike mechanical clocks which depend on the construction of the pendulum, or quartz clocks that depend on the properties of an individual quartz crystal, every cesium atom in the universe is guaranteed to be identical to every other cesium atom in the universe, with the same basic separation between energy levels. If you have a frequency source, and tune it so that it is at exactly the frequency that cesium atoms like to absorb, you can use that frequency to measure the progress of time-- to be specific, every 9,192,631,770 oscillations of the light absorbed or emitted by a cesium atom moving from one hyperfine ground state to the other is one second.
GPS relies on precise timing-- your GPS receiver determines its position on the surface of the Earth by measuring the time required for signals from at least three different satellites to reach its position. The orbital positions of the satellites are well known, and light travels at a fixed speed, so the travel time determines your distance from three of those satellites. That, in turn, fixes your position at a specific point on the surface of the Earth.
So, where do the magnets come in? Well, in order for the clock to work, you need to take a bunch of cesium atoms, expose them to the light that you're hoping to use as a reference, and see if they move from one state to the other. In order to know this, though, you need to know which state they started in, and which state they ended up in. Magnets can help you do this state selection, as shown in this schematic of an atomic clock taken from the PDF file at the bottom of this NIST page:
The clock starts with an oven containing a chunk of cesium. Atoms from the oven stream out in an atomic beam, but the atoms are initially distributed over many states, when clock operation demands that they be in a single well-specified state. In older atomic clocks, and the clocks on the GPS satellites, the specific state of interest is selected out by using magnets to deflect the other states out of the beam, so they don't enter the area where they are exposed to the light.
The physics behind this deflection is the same as the Stern-Gerlach experiment, done by Otto Stern and Walter Gerlach in 1921. Stern and Gerlach sent a beam of silver atoms between the poles of a tapered magnet, so that the magnetic field was stronger on one side than the other. The beam of atoms split into two beams, which they detected by letting them fall on a photographic plate.
As is typical of pioneering experiments, Stern and Gerlach actually measured something other than what they thought they were measuring-- they thought they were just seeing an effect cause by an electron orbiting the nucleus of a silver atom, with atoms whose electrons orbited clockwise experiencing a different force than atoms whose electrons orbited counter-clockwise. but the planetary type model behind that picture doesn't work. Instead, what they discovered was the intrinsic spin of the electron, which has its own angular momentum as if it were a spinning ball of charge. That angular momentum can take on one of two possible values, and in the case of silver, leads to a force on an atom between Stern and Gerlach's magnets that is either up or down, depending on the particular electron.
Stern and Gerlach were fortunate that they were using silver, which only has two states. Other atoms have more complicated level structures, and split into more than two beams, but the essential physics is the same. This splitting is the basis for the state selection in an atomic clock-- the cesium atomic beam passes through a Stern-Gerlach magnet, and then a pinhole blocks everything but a single state that happens to be bent onto exactly the right trajectory.
After the cesium atoms are exposed to the light source, they enter a second set of magnets, which again splits the atomic beam, with the atoms that have changed states being sent one way, and atoms that have not changed states sent another way. Measuring the fraction that changed tells you how close the frequency of the light is to the frequency the cesium wants to absorb, and allows you to correct the frequency to keep it right on target. That, in turn, provides an absolute reference for the GPS satellite to use in determining the time, which it encodes into the signal that it broadcasts to your GPS receiver.
So, while satellites are the really important part of GPS, and the correct answer to the question, the satellites wouldn't work without magnets. And now you, too, know enough to be confused by a simple and straightforward poll question.
(Anticipating a possible comment: the schematic shown is for a Ramsey-type clock, with the atoms interacting with the light field twice. A comment in one of the linked references suggests that the actual GPS clocks may be Rabi-type clocks, with a single large interaction region (though I could be misreading that). I couldn't find a picture of the clocks used in GPS, though, so you'll have to live with this one.)
相关英语学习内容
大学短文&|&妙招短文&|&提高自己&|&妙招短文&|&美容护肤&|&健康生活&|&科学短文&|&
Sex性生活&|&健康生活&|&癌症短文&|&积极心理&|&心脏病&|&幸福短文&|&健康生活&|&
匿名发表&&
您还能输入300字
英语短文阅读排行
1111111111
1111111111
1111111111
我们也在这里：您好，欢迎来到新东方
英语口语技能训练练习话题精编,口语考试话题详细指导
来源：互联网
1. Do you have a hobby? Can you tell us something about it? What do like to do in your spare time?
I have many hobbies, such as playing football, going fishing, climbing mountains and so on, and the one that I like best is playing football. When I play football with others I can make friends with those who come from different departments. Meanwhile I can learn how to forgive others’ mistakes during the match, which will help me to become more endurable in the daily life. Besides, I can practice my ability to work efficiently with my fellows, because it seems that we can win the game only if we can work together in a powerful team. In a word, I can reap the great benefits of this hobby.
During my spare time, I would like to go to the library. I can learn other subjects in there so that I can improve my knowledge structure, which will provide me with a better chance to find a good job in the future. What’s more, I can get more references about my major, and by this way I can also make my major improved greatly.
2. What’s your major? Why do you choose it?
My major is legal science which is also my favorite major. In this field, we are able to learn a lot of knowledge. There are many subjects we have to learn, such as Criminal Procedure Law, Civil Law, Law of Civil Procedure, General Rules of the Civil Law, Marriage Law, International Law, Jurisprudence, philosophy, logic, history, politics and so forth..
The following is the reasons why I choose it:
First of all, I am interested in my major, I love watching the TV programs about laws since I was in the middle school and it expands my horizons. Studying this major makes me know how to become a useful, helpful and happy person, for very day, you are ready to help others which makes you feel so happy that you find you have made your value come true .
In addition, our society is in a great need of the skilled workers and experts in laws, because our country develops very rapidly and we need law to maintain peace and order, to protect the rights of citizens, to secure justice, to punish wrong-doers and to make our good laws be applied justly no matter what cases might be. Therefore, it is significant to take legal course to make contributions to the development of our socialist undertakings. Last but not least, as far as I am concerned, it’s good for my future career. I think I’ll have a good job in the future. I will become a lawyer though the studying my major, which can make me earn lots of money. So I choose legal science as my major. And I think my choice is right. And most important, it will lead me to live a happy and wealthy life.
3. How do you like university life? Which aspect of university life do you find most interesting (stimulating /challenging /exciting /enjoyable)?
With the expectation of the university, I came to Xinyang Normal University. I love this university at the sight of her, and I think the university life is colorful, stimulating, exciting, enjoyable, interesting, meaningful, and so on. Most important of all, I find college English class is most exciting for me.
First of all, college English class is student-centered and only speaking English. In middle and high schools, English classes were teacher-centered and bi-lingual, English teachers explained English grammars and new words in Chinese from the beginning to the end of each class, and we had little chance to speak English even in class. However, here English teachers give speeches in English, and we students are required to answer some questions, discuss some topics, and exchange our ideas, etc. only in English in class. I have to practice my spoken English as often as possible, day after day, now I find I can state my opinions clearly in spoken English in public. How pride I feel!
Secondly, college English class is more interesting and full of activities, such as role-playing, English competitions about telling stories, jokes or tongue twisting. Students are active to take part in all of these class activities to show their abilities and develop their hobbies. We come to class not only for knowledge but also for fun. How happy I am!
In all, college English class is completely different from those in middle and high schools, it’s so exciting and I do love it. I bet I will improve my English and achieve more here.
4. Are you satisfied with your present accommodations? Give your reasons.
What kind of accommodations would you like to have?
From my point view, I’m quite satisfied with our accommodation. My dormitory room faces south and has a lot of sunshine in fine weather. It also has a very good view of the garden in front of the building and the mountains in the distance. It makes me feel good when I look the lovely grass, flowers and trees in the garden. The color of the mountains changes with different seasons and in different weather. I really enjoy watching the view from my room.
But there are some aspects need to be improved. Above all, our dormitory is not big enough. When everybody is in the room, there simply is not enough space for us to move around. And with six people in it, there isn’t much privacy for anyone.
We even don’t have a washroom in it .So it’s not convenient for us, especially in winter and summer. And the water and electricity supply are usually cut off for some unclear reasons. Everyday we have to go to bed before half past ten. That’ too early! S o we are restricted to do what we need to do after ten thirty. In a word, our canteens are quite good. First of all, the food is quite cheap and the services meet most of our needs. But some canteens are so small that have to wait in line to get our food.
In my opinion, a good student apartment should have a relatively large living room and three or four small single bedrooms. This design will provide enough space for meetings and gatherings while at the same time give each student his or her own room. It should have a washroom and we should have water and electricity supply all day long. And we also can get our food without waiting in line.
In my university, students have different types of accommodation depending on their status. Undergraduate students generally share dormitory rooms six to a room, and master’s students four to a room. New apartment houses are also available to students who pay an additional rent.
5. What job do you think is the best for you after you graduate?
I think the best job for me is to be a teacher after graduation. When I was a child, I had dreamed to be a high school teacher. Now I can come to Xinyang Normal University to receive further education and I major in Study of History. It looks like that my dream will come true in the near future.
As a teacher, I can give what I have learnt to my students, who will make contributions to our society. Thinking about it, I will be very proud of being a teacher. And, what’s more, I can become an actor just on the small platform in the front of the classroom, which will make my life much colorful. And then, what mostly makes me choose to be a teacher is that I can share some new ideas with the young people, and by this way I will be young forever in my mind.
6. What is your most important consideration when looking for a job?
Actually, many factors contribute to job satisfaction, such as a high salary, good promotion prospects, pleasant and friendly working atmosphere, suitability for one’s professional talents，and personal interests etc. For many people, money or good promotion prospects may be their most important consideratio but as for me, what is important is to do something that I enjoy. I hear stories all the time about people who change their jobs because they realize that they don’t like them after they have started. If you don’t like what you’re doing, you are going to be miserable. You cann’t make the best use of your talents and you will get nowhere in your work. So when choosing a job, I think, we’d better make sure that we know where our interest lies, only by doing so, can we do very well in our work and enjoy our work most.
7. What kind of activities do you take part in during your free time?
Many students may feel that college life is boring. They do not know how to deal with plenty of spare time. But I think the college life will become wonderful as long as we make it meaningful. In fact, we can do all kinds of activities which we are interested in. Do not be nervous.
(1) In my spare time, I often do sports. Doing sports can enhance our physical (mental) development. It can keep fit and make us staying in health. I’ll learn some self-defense skills from it. By doing sports, I also learn how to communicate and interact with others.
I like running. It is exciting. I feel close to nature when running .And it shows what upper limit human physique can reach after finishing a full running.
Sometimes, I often play basketball, football, badminton table tennis, and so on. You know, table tennis is very popular activity on campus. It is a national sport. Not only do students like it, but many teachers like it. Playing table tennis can train my brain, especially my eyes . After studying for a long time, My eyes are tied and hurt. So it is good choice to play table tennis with my classmates for relaxing ourselves.
I’m a big basketball fan, even though I’m not good at playing basketball myself. I like Yao Ming, so I love to watch the NBA on TV whenever I get a chance.
(2) In my free time, I often surf on the internet. With the development of computers throughout the world, more and more people have access to the Internet. I know it has disadvantage to spend too much time using it. But I just use it to get a lot of information by browsing different websites.
In fact, the Internet has changed our conventional ways for work, communication, entertainment and expression. Apart from using the Internet for professional purposes, I also use it to communicate with families and friends by sending and receiving e-mails, talking with others and playing games such bridge or chess with partners or opponents they don’t see. I also use the BBS to express my opinions in ways otherwise impossible.
In general, spending too much time surfing on the interest is not good to a person. We should have a right attitude to it and make use of it correctly for our study.
Studying in college is a brand new start of our life. We can continue to study hard for the better scores. If we want to show our talents and skills we can join in all kinds of activities. By so , we can have a wonderful college life!
8. Is it necessary for students to take part in the social activity during the free time?
Everybody knows that study is one of the most important things for the young people, and a lot of people think that young men should study everyday to get a good score. But I do not agree with such an idea, my opinion is that the social activity and study are good friends.
I have 3 main aspects to support my idea.
Firstly, the purpose of study is to do more contributions to the society, is to serve for the work. We learn more and more things in order to work easier and easier in the future, so social activity is the checking standard of study.
Secondly, the social activity can make us know what is our weakpoint and what we should learn in the future. For example, if I can not use computer in my social work, I must ask myself to learn it well so as to improve my work.
Finally, the social activity is also a kind of rest for us after study. From what has talked above, we can safely draw a conclusion that the social activity is a good partner of study, we should make use of the relations between them to create a good future.
9. Can you tell us something about the after-class activities at your college (university)?
When the classes are over, students burst out of the classroom buildings. Tired after a whole of serious study, they mostly spend one or two hours to relax and refresh themselves. If you take a walk on campus, you will get an idea about what students do after class.
On the playgrounds, various kinds of sports activities are going on. You will see students jogging or playing ball games. Some of them may only be practicing, some are competing seriously against each other.
On the weekends, members of various clubs meet at this time. Some students are learning painting, calligraphy or paper-cut, while others simply sit around and talk. The drama group is rehearsing and the school chorus is practicing. And there is also a film show on Saturday.
On Sundays or holidays we often have concerts, plays, or parties. Sometimes we organize picnic, climbing mountains, visits to exhibitions of factories. From time to time we invite professors from different fields to give lectures, they are qualified, professional and helpful.
Through the after-class activities, we widen our horizon, makes friends, have fun at the same time, the most important is, we learn many thing that we can’t in class. It is these activities that make our college life colorful and unforgettable.
10. What kind of after-class activities are you interested in?
I'm interested in sports after class because we have to relax after we study in class. Sports are good and necessary for our body and mental. I like long-Running around the playground or along the road because it is full of energy and power, I enjoy climbing the steep and high mountain to see the beautiful nature on the I'm fond of skating on the snow or ice to balance myself after a long time exercise, standing the pains an I try to experience the extreme-sports here and there if possible to make my blood boiling...... I should do something to make myself to be somebody, or at least to build up my mind and body to meet the challenges in the new life.
温馨小贴士：
1. 咨询电话：（每天 9:00-18:00）
2. 上海新东方官网：
（责任编辑：Lynne）
新东方培训机构提供、英语、、、 、、、,等等课程的学习。课程多，分类细，方便大家的选择。满足不同阶段的学习需求。
上海新东方学校 推荐:
新东方上海学校：微服务 （微信号：XDFSHWFW）
报班扫一扫，优惠优先知，手机报名不排队、更便捷
版权及免责声明
①凡本网注明"稿件来源：新东方"的所有文字、图片和音视频稿件，版权均属新东方教育科技集团（含本网和新东方网）
所有，任何媒体、网站或个人未经本网协议授权不得转载、链接、转贴或以其他任何方式复制、发表。已经本网协议授权的媒体、网站，在下载使用时必须注明"稿件来源：新东方"，违者本网将依法追究法律责任。
② 本网未注明"稿件来源：新东方"的文/图等稿件均为转载稿，本网转载仅基于传递更多信息之目的，并不意味着赞同转载稿的观点或证实其内容的真实性。如其他媒体、网站或个人从本网下载使用，必须保留本网注明的"稿件来源"，并自负版权等法律责任。如擅自篡改为"稿件来源：新东方"，本网将依法追究法律责任。
③ 如本网转载稿涉及版权等问题，请作者见稿后在两周内速来电与新东方网联系，电话：010-。
托福热点排行}