16.Infrared scanning technology may be brought back into operation because of      .

     A.the desire of farmers to improve the quality of their produce

     B.growing concern about the excessive use of pesticides on crops

     C.the forceful promotion by the Department of Agriculture

     D.full support from agricultural experts

E

There are various ways in which individual economic units can interact with one another. The basic ways may be described as the market system , the administered system , and the traditional system .

In a market system individual economic units are free to interact among each other in the marketplace. It is possible to buy commodities (商品)from other economic units or sell commodities to them . In a market , transactions(交易)may take place via barter or money exchange . In a barter economy , real goods such as automobiles , shoes , and pizzas are traded against each other . Obviously , finding somebody who wants to trade my old car in exchange for a sailboat may not always be an easy task . Thus , the introduction of money as a medium of exchange eases transactions considerably . In the modern market economy , goods and services are bought or sold for money .

An alternative to the market system is administrative control by some agency over all transactions . This agency will issue commands as to how much of each goods and service should be produced , exchanged , and consumed by each economic unit . Central planning may be one way of administering such an economy . The central plan , drawn up by the government , shows the amounts of each commodity produced by the various firms and allocated (分配)to different households for consumption(消费). This is an example of complete planning of production , consumption , and exchange for the whole economy .

In a traditional society , production and consumption patterns are governed by tradition : every person’s place within the economic system is fixed by parentage , religion , and custom . Transactions take place on the basis of tradition , too . People belonging to a certain group may have an obligation to care for other persons , provide them with food and shelter , care for their health , and promote the education . Clearly , in a system where every decision is made on the shelter , care for their health , and promote the education . Clearly , in a system where every decision is made on the basis of tradition alone , progress may be difficult to achieve , A stagnant(停滞的)society may result .

12.The laughter made by both the speaker and the listeners showed      .

     A.the problem of the “Mad Cow Disease” would be solved in an easy manner

     B.both sides felt something funny

     C.the listeners were making fun of the British speaker-Mr Stone

     D.Mr Stone’s speech was a successful one

D

Even plants can run a fever , especially when they’re under attack by insects or disease . But unlike human , plants can have their temperature taken from 3,000 feet away -straight up . A decade ago , adopting the infrared (红外线)scanning technology developed for military purposes and other satellites , physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress . The goal was to let farmers precisely target pesticide (杀虫剂)spraying rather than rain poison on a whole field , which invariably includes plants that don’t have pest (害虫)problems .

Even better , Paley’s Remote Scanning Services Company could detect crop problems before they became visible to the eye . Mounted on a plane flown at 3,000 feet at night ,an infrared scanner measured the heat emitted by crops . The data were transformed into a color-coded map showing where plants were running “fevers” . Farmers could then spot-spray , using 50 to 70 percent less pesticide that they otherwise would .

The bad news is that Paley’s company closed down in 1984 , after only three years . Farmers resisted the new technology and long-term backers were hard to find . But with the renewed concern about pesticides on produce , and refinements in infrared scanning , Paley hopes to get back into operation . Agriculture experts have no doubt the technology works . “This technique can be used on 75 percent of agricultural land in the United States ,” says George Oerther of Texas A& M, who recently retired from the Department of Agriculture , thinks remote infrared crop scanning could be adopted by the end of the decade . But only if Paley finds the financial backing which he failed to obtain 10 years ago .

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