为了支持不同的传输介质,快速以太网提供了3种技术标准,即100BASE-T4、 100BASE-TX、100BASE-FX。100BASE-T4使用 (29) 。
A. 4对、3类线
B. 2对、3类线
C. 4对、5类线
D. 2对、5类线
The devastating effects of earthquakes on human lives and property have encouraged the search for earthquake prediction. This challenge remains and contemporary seismologists continue to seek reliable methods for pinpointing the time, place and magnitude of individual quakes. One prediction technique involves an analysis of the recurrence rates of earthquakes as indicators of future seismic activity. Earthquakes are concentrated in certain areas of the world where tectonic plates such as the Pacific Plate, the Eurasian Plate and the African Plate meet and create fault zones and it is in these areas that seismologists focus their investigations. The tectonic plate model provides another tool for earthquake prediction by calculating the accumulated strain at plate boundaries. When the strain reaches a certain magnitude the pressure must be released and it is therefore hypothesized that in such eases an earthquake is imminent. The search for premonitory phenomena has received particular attention. In contrast to the ancient Greeks and Romans, who relied on the howling of dogs as a warning sign, modern seismologists have focused on physical evidence for an impending earthquake. Evidence of plate strain can be found by measuring relative movements in geodetic stations, while chemical changes also offer signals for seismologists. Using chemical-detection techniques, scientists established a link between the rise in the concentration of radon gas in mineral water and the subsequent earthquake. Analysis of the changes in magnetic properties and conductivity of rocks provides further data for prediction. The electrical and magnetic properties of crustal rocks particularly sensitive to strain and studies measuring changes which occur in these properties have provided promising results. The conductivity of crustal rock is determined by the degree to which the rock is saturated with fluid and the electrolytic properties of those fluids. Before large earthquakes, small fractures develop in rocks, which change the quantity of fluid present. These changes can be measured and provide useful predictive data. However, similar changes in the fluid-bearing capacity of rock can occur as a result of other factors such as changes in the water table, and therefore this technique is not entirely reliable. The belief that the behavior of birds, eats and dogs provides evidence of imminent earthquakes has recently gained credence. It is hypothesized that the animals are sensitive to the seismic waves which precede major quakes. In zones where earthquakes are known to occur, improved construction techniques can significantly reduce the effects of seismic waves. If more accurate information regarding the time and magnitude were available, governments could take even more effective measures to reduce the impact on human life. If an entirely accurate prediction technique became available, there would be significant social and political implications. An earthquake prediction in a major urban area would require governments to provide an effective evacuation strategy, necessitating massive resource and political will. Which of the following is true
A. Earthquakes only occur in the Pacific, Eurasian, and African Plates.
B. Earthquakes are caused by the tectonic plate model.
C. An increase in the level of radon gas in water always indicates an imminent earthquake.
D. The devastation of earthquakes prompted the set, king for reliable prediction methods.
ATM提供一种和应用独立的服务,主要表现在 (31) 。
A. 空间独立和时间独立
B. 时间独立和语义独立
C. 语义独立和空间独立
D. 传输独立和空间独立
The word "bankruptcy" comes from banes rotta, Italian for broken bench. The custom was that when a medieval trader failed to pay his creditors, his trading bench was broken. Since bankruptcy was taken off the street and put into the statute book, it has become rather more complicated. Bankruptcy is as necessary for capitalism as profit; together they make up the stick and carrot which persuade businessmen to work. In Europe the accountants and lawyers who make a living from overseeing bankrupt companies expect the coming year to provide a bumper crop; in America bankruptcy courses are among the most popular at business schools. Only in Japan are experts talking about a possible decline in bankruptcies. Analyzing companies involves much the same task worldwide: look at the accounts and you will get some idea of how much or how little money a firm makes. Bankruptcy laws, however, vary enormously from country to country, mainly because each starts from different historical perspectives. Yet they all tackle the same issues—and the most fundamental is how friendly the law should be to the debtor. Countries whose bankruptcy laws are based on the British model view bankruptcy primarily as a way to recover creditors’ money. Typically, the courts replace the bankrupt firm’s management with a liquidator or a receiver whose mission is to pay back creditors as quickly as possible. England’s first bankruptcy law was an "act against such persons as do make bankrupt". For centuries British bankrupts went to debtors’ prison. Continental countries also took the creditors’ side. In contrast, one of America’s attractions to immigrants was its very lack of a debtors’ prison. Bankruptcy is still viewed in America as a side-effect of entrepreneurship. Managers of a bankrupt firm are often allowed to stay on. Cynics reckon that some well-know businessmen have made a career ont of taking companies into and out of bankruptcy. The aim of American bankruptcy law is rehabilitation: to reorganize the company so that it can continue to trade, rather than .to see that the creditors are paid off. Thus, while an ailing American company can opt for liquidation by filing under the chapter 7 of the Bankruptcy Code, it can also file under chapter 11 to seek protection from its creditors. Once a firm has gone into chapter 11 its management has to produce a reorganization plan: the creditors are arranged into committees to vote on it. These can become scrums where the various creditors’ relative seniority varies according to their lawyers’ eloquence. Fans of the American system argue that it gives companies a chance to recover. Critics say that American law favors the same managers who bankrupted the firm, that it encourages lawyers to prolong bankruptcy protection, that it favors big bankers over smaller trade creditors, and that shareholders, the last to be paid in liquidation, gain at the expense of debt-holders. In Paragraph One, "Since bankruptcy was taken off the streets and put into the statute book" means______.
A. creditor no longer broke the bankrupt’s bench on the streets but wrote down his name
B. creditor had debtor’s name carved on a statue
C. the punishment on a debtor was bounded by law instead of spontaneous action
D. it took more procedures to ask a trader to pay his creditors