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A．欧拉回路B．哈密尔顿回路C．最大匹配D．最小生成树
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一个计算机公司开发的项目需要完成7个任务，其中某些任务只能在其他任务结束之后才能开始。设这7个任务的集合为A={a,b,c,d,e,f,g}，考虑任务集合A上的偏序≤：任务x≤任务y，当且仅当任务y在任务x结束之后才能开始。这7个任务关于该偏序关系≤的哈斯图如图5-5所示。在下列执行次序中，不能按照要求完成这个项目的执行次序为______。
A．进程请求I/O→独立于设备的软件→中断处理程序→设备驱动程序→硬件B．进程请求I/O→独立于设备
The United Nations Conference on Drag Abuse that took place earlier this year in Vienna was a very productive meeting. As nerve before, the nations of the world demonstrated a willingness to put aside ideological and individual differences to confront a common threat.
Most previous international gatherings on this subject have not seen the same intensity of delegate interest. Many nations have gone through a shock of recognition. A decade ago, only those nations identified as "consuming countries" were thought to have a serious drug problem. Today, not only have many "producing countries" also become "consuming countries", but many have witnessed the growth within their borders of drug trafficking gangs (often allied with terrorists) so powerful they present a danger to the state's stability. Many developing countries now have the worst of both worlds, in that they grow their own narcotics and addict large numbers of their own people. There is a growing sense of fright in many governments that matters are out of control and the single way to recover is through cooperation with other countries.
The high points of the conference were the drafting of two documents, both of which were adopted without a dissenting vote. One was a joint declaration of intent to combat drug abuse and trafficking. The other consisted of many detailed suggestions for particular regional and national policies.
Overall, the conference developed a two-level action plan. The focus was on ways to curb the demand for dangerous drugs and on methods of destroying or at least interrupting the distribution process.
On the demand side, the delegates recommended the establishment of a system for collecting information on the nature and scope of narcotics use. In addition to that drug education should be taught in schools and those governments and labor organizations should act together in the anti-drag campaign in the workplace. The delegates also recommended strict adherence to international agreements to curb the supply of narcotics.
Striking feature of the UN Conference on Drug Abuse is that______.
Section B
Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.
If you have gone on a diet and reached your goal, chances are good that when you stop dieting you will regain all the weight you lose. After several weeks on a low-calorie diet—900 calories or fewer— the body conserves energy by showing the speed at which it burns calories. This slow-down explains in part why your weight loss may cease after a few weeks. When you eventually return to eat a normal amount of food, your body may continue to burn calories at the slower rate, storing the remaining calories as fat. So if you are on a strict diet, your body may need fewer calories to maintain the same weight; losing weight becomes more difficult.
Doctors know that as you gain weight the fat cells in your body (most of us average 30 billion of them) become enlarged. But there is a limit to how big a fat cell can get, and very fat people develop additional fat cells—something more than 100 billion. It now appears that you can add fat cells at any point during your life, although the number you have is influenced by a combination of your history of dieting and your genetic makeup.
Fat cells differ distinctly from other cells in that they are made mostly of fat instead of protein and apparently they never go away, even after dieting. Instead, they merely shrink. Dr. Jukes Hirsch of Rckefeller University has examined the body tissue of very fat people who have lost weight, and found that it resembles that of starvation victims. Perhaps, he supposes, it is the billions of undersize, "hungry" cells that drive many formerly fat people off their diets.
New research reveals that your hungry cells aren't the only signal senders that tempt you toward the refrigerator. Another culprit may be the hormone insulin. Insulin tums sugar and fat into fuel for the body. In addition, some researchers believe that high levels of insulin are a factor in hunger and appetite—and may drive you to overeat.
Exercise helps maintain your weight and seems to bring insulin levels down, says Dr. Donald S. Robertson, a medical director. "Any weight -loss program must fail," he said, "unless it incorporates a certain amount of exercise."
When you stop dieting you will regain the weight you lost because ______.
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