2．无级变速是在变速范围内任意连续地变换速度，性能优于传统的档位变速器．如图所示是截锥式无级变速模型示意图，两个锥轮中间有一个滚轮，主动轮、滚轮、从动轮之间靠着彼此之间的静摩擦力带动．当位于主动轮与从动轮之间的滚轮从左向右移动时，从动轮转速降低，滚轮从右向左移动时从动轮转速增加．当滚轮位于主动轮直径D₁，从动轮直径D₂的位置上时，则主动轮转速n₁，从动轮转速n₂之间的关系是 (　　 )

A． 　　　　　　　　B．

C.　 　　　　　　　D．

　 3．如图所示，三个同心圆是点电荷Q周围的三个等势面。已知这三个圆的半径成等差数列，A、B、C分别是这三个等势面上的点，且这三点在同一条电场线上。将电量为q=+1.6×10^-6C的电荷从A点移到C点，电势能减少1.92×10^-5J.

若取C点为零电势点(=0V)，则B点的电势(　　 )

A．一定等于6V　　 B．一定低于6V

　　 C．一定高于6V　　 D．无法确定

　 4．如图所示，一不可伸长的轻绳长为L，一端固定在O点，

另一端系着一个质量为m的小球。开始小球处于A点

细绳恰好拉直(绳中无拉力)，现让小球由静止自由释放，

则小球运动到O正下方的C点时绳子的拉力大小为(　　 )

　　 A．4mg　　　　　　

　　 B．3.5mg　　　　　

　　 C．3mg　　　　　　

　　 D．2.5mg

1．如右图所示，位于竖直平面内的固定光滑圆环轨道与水平面相切于M点，与竖直墙相切于A点，竖直墙上另一点B与M的连线和水平面的夹角为60⁰，C是圆环轨道的圆心．已知在同一时刻：a、b两球分别由A、B两点从静止开始沿光滑倾斜直轨道AM、BM运动到M点；c球由C点自由下落到M点；则：(　　 )　　　　　　　 　　　　　　　　　　　

A．a球最先到达M点　　　　　 B．b球最先到达M点

C．c球最先到达M点　 　　　　D．b球和c球都可能最先到达M点

第二节　　　 书面表达(满分25分)

　　 高三阶段学习比较紧张，正确的学习方法尤为重要。下表显示了两位同学不同的学习方法，请简述并发表你的观点，词数在100左右。文章开头已给出。

参考词汇：

1.attentively 专心　 2.energetic 精力旺盛　centrate on 集中注意力　 4.effrctively 有效地

　　 Li Hua and Wang Hai are two students of Senior Three. Both of them work hard but they have different learning methods.__________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

第一节　　　 任务型读写(共10 小题，每小题1分，满分10分)

Robot revolution

　　 The day that a robot wakes you up, cleans your room and walks your dog might still be a few decades off. But increasingly, engineers are saying that robots are going to make the leap from the factory floor to your family room.

Companies like Sony and General Electric are working on designs for small robots. Products like the Roomba, a robot that can clean floors, are flying off the shelves. On the cover of a recent issue of Scientist American magazine, Bill Gates predicted the “Dawn of the Age of Robots”.

What’s behind this new era(时代)？It’s partly a matter of technology. Devices that can recognize and respond to a human voice have been developed. There are now a few different ways for robots to move around. They can walk , crawl or ride on wheels. They are being made smaller and smaller. They are also becoming more and more energy efficient.

A bigger part of the story is on the demand side. From the day Robert Adler invented the television remote control in the 1950s, people around the world have tirelessly searched for ways to get lazier.

Also take into consideration the increasing wealth of rich people, the time appears ripe to introduce robots to ease our daily lives.

To be sure, robots that walk on two legs and talk people are still too complex for our present engineering abilities. Today’s robot revolution is to make them for everyday use. Robots will do basic housework such as cleaning or gardening, or just help you have more fun on the basketball court.

What makes a robot different from an ordinary cleaning machine is not the presence of computer chips(芯片). Nowadays even your microwave has a computer chip. It is the ability to sense and make changes to the environment in real time.

For example, a floor-cleaning robot should be able to sense your scared cat and move out of the way. Today’s computing ability is, for the first time, able to make machines that could “think”, at least in certain limited ways.

第二节　 完型填空　 (共20 小题；每小题1.5分，满分30分)

When I entered Berkeley, I hoped to earn a scholarship. Having been a Straight-A student, I believed I could 36 tough subjects and really learn something. One such course was World Literature given by Professor Jayne. I was extremely interested in the ideas he 37 in class.

When I took the first exam, I was 38 to find a 77, C + - plus, on my test paper, 39 English was my best subject. I went to Professor Jayne, who listened to my arguments but remained 40 .

I decided to try harder, although I didn’t know what that 41 because school had always been easy for me. I read the books more carefully, but got another 77. Again, I 42 with Professor Jayne. Again, he listened patiently but wouldn’t change his 43 .

One more test before the final exam. One more 44 to improve my grade. So I redoubled my efforts and, for the first time 45 the meaning of the word “thorough”. But my 46 did no good and everything 47 as before.

The last hurdle(障碍) was the final. No matter what 48 I got, it wouldn’t cancel three C+-pluses. I might as well kiss the 49 goodbye.

I stopped working hard. I felt I knew the course material as well as I ever would. The night before the final, I even 50 myself to a movie. The next day I decided for once I’d have 51 with a test.

A week later, I was surprised to find I got an A. I hurried into professor Jayne’s office. He 52 to be expecting me. “If I gave you the A’s you 53 , you wouldn’t continue to work as hard.”

I stared at him, 54 that his analysis and strategy(策略) were correct. I had worked my head 55 , as I had never done before.

I was speechless when my course grade arrived: A-plus. It was the only A-plus given. The next year I received my scholarship. I’ve always remembered Professor Jayne’s lesson: you alone must set your own standard of excellence.

36. A. take　　　　　　 B. discuss　　　　　　 C. cover　　　　　　　 D. get

37. A. sought　　　　　 B. presented　　　　　 C. exchanged　　　　　 D. obtained

38. A. shocked　　　　 B. worried　　　　　 C. scared　　　　　　　 D. anxious

39. A. but　　　　　　 B. so　　　　　　　　 C. for　　　　　　　　 D. or

40. A. unchanged　　　 B. unpleasant　　　　 C. unfriendly　　　　　 D. unmoved

41. A. reflected　　　　 B. meant　　　　　　 C. improved　　　　　 D. affected

42. A. quarreled　　　　 B. reasoned　　　　　 C. bargained　　　　　 D. chatted

43. A. attitude　　　　　 B. mind　　　　　　 C. plan　　　　　　　　 D. view

44. A. choice　　　　　　 B. step　　　　　　　 C. chance　　　　　　 D. measure

45. A. memorized　　　　 B. considered　　　　 C. accepted　　　　　　 D. learned

46. A. ambition　　　　　 B. confidence　　　　 C. effort　　　　　　　 D. method

47. A. stayed　　　　　　 B. went　　　　　　　 C. worked　　　　　　 D. changed

48. A. grade　　　　　　 B. answer　　　　　　 C. lesson　　　　　　 D. comment

49. A. scholarship　　　　 B. course　　　　　　 C. degree　　　　　　 D. subject

50. A. helped　　　　　　 B. favored　　　　　　 C. treated　　　　　　 D. relaxed

51. A. fun　　　　　　　 　B. luck　　　　　　　 C. problems　　　　　 D. tricks

52. A. happened　　　　　 B. proved　　　　　　 C. pretended　　　　　 D. seemed

53. A. valued　　　　　　 B. imagined　　　　　 C. expected　　　　　 D. welcomed

54. A. remembering　　　 B. guessing　　　 　　　C. supposing　　　　　 D. realizing

55. A. out　　　　　　　 B. over　　　　　　　 C. on　　　　　　　　 D. off