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数据库系统中定义和描述数据库逻辑结构的语言称为______。

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战略数据规划是信息系统建设必须做好的基础工作，它主要完成一个不受技术变化影响的、稳定的______。

Directions: Write an essay of 160--200 words based on the following drawing. In your essay, you should1) describe the drawing briefly,2) explain its intended meaning, and then3) give your comments.You should write neatly on ANSWER SHEET 2.

[A] In our time women have an average lifespan of almost 80 years; double of what it was in the last century. Motherhood can be postponed and in theory marriage can be postponed. Women in the US are studying more than men and they may become main breadwinner in the near future.[B] Many women go through life thinking, consciously or unconsciously, that a man will solve all their problems,"Once we are married, everything will be OK. " This attitude only set us up for failure. Men are not princesready to take any challenge to rescue the princesses; they are human beings with their own needs and fears.[C] Carrie was wondering in her bedroom about the comment that her friend, New York socialite Charlotte York, made "Women want to be rescued. " Carrie wonders, "Is that true Is that the only thing women want Rescued by whom If the prince did not kiss Snow White, would she have been frozen forever or would she have woken up anyway and moved on" Snow White probably had no other chance, but we do.[D] No wonder our society has changed. On the other hand, our values have not fast enough and many women, more so Hispanic women, are just waiting to be rescued by the prince. These women have not realized they no longer need to be rescued; they need a man for other reasons, not to take care of them.[E] Women in our society have so many options that we do not need anybody else to rescue us; we are the only ones that can rescue ourselves. If you have areas of your life that you want to improve, go ahead; do it for you and for you only, or accept yourself as you are. Do not be so naive that you think someone else can take care of all your problems. Life does not work like that. Live life to the fullest, be happy with who you are and you will see that if you are happy with yourself, you will make others happy, including your man.[F] Our society has changed in a remarkable way in the last 50 years or so. And there are many reasons for it. At the beginning of the 20th century women’s lifespan was about 40 years. Therefore, life needed to start earlier if a woman were going to live for only 40 years; motherhood was a priority. Men used to work and women stayed at home and took care of them and their kids. Women could not survive without a man; women needed to be rescued.[G] Women are caregivers. We are strong and smart and we have the ability to take care of ourselves; we do not need to be rescued by anyone. When we are giving our power to others in exchange for security, we are also giving up our freedom. Are you waiting to be rescued Do you ever think like thatOrder: 41

There are many innovations turning up in the latest experimental and production electric cars, affecting everything from batteries to motors to control systems. The need to make them all work together is prompting a complete rethink about the way cars should be designed and manufactured, and it is unclear which technologies will dominate as the constraints imposed by internal combustion engines give way to the new limits and possibilities associated with electric propulsion. (46) But one group of engineers have stuck their necks out and declared that a particular technology, the electric hub motor, is likely to become the most widely used drive system.At this week’s Deutsche Messe technology show in Hanover, researchers at the Fraunhofer Institute displayed an electric vehicle which they are using as a test platform to investigate new vehicle systems. (47) It includes electric hub motors, which they have developed to be markedly more powerful than any such motors currently available. The motors have all the necessary power and control systems integrated into the wheel hub, greatly reducing the number of connections between the hub motors and the rest of the vehicle.(48) Because hub motors can deliver power independently to each wheel, tricks like four-wheel-drive are possible, and with software monitoring each wheel, stability and traction control can also be built-in. Besides dispensing with the traditional engine bay on a car, hub motors save space and weight because there is no need for a mechanical transmission, with its driveshafts and differential units.(49) Some critics of the technology think having heavy electric motors in the wheels of cars will have a negative effect on vehicle handling. But Hermann Pleteit, a project manager with one of the 33 Fraunhofer research centres that have teamed up to work on the experimental car, says the chassis and many other parts of the vehicle can be configured in such a way to compensate for this.Several carmakers and component suppliers are interested in hub motors. Michelin, for one, is developing a system it calls the Active Wheel. (50) As well as an electric motor to drive the wheel, it contains a second electric motor to operate an active suspension system that is also built into the wheel hub. Michelin reckons this arrangement, which is now being tested in cars, could make other conventional parts, like shock absorbers, unnecessary. As well as an electric motor to drive the wheel, it contains a second electric motor to operate an active suspension system that is also built into the wheel hub.