单选题
The most pressing nuclear energy issue is the disposal of nuclear waste. Even if all the reactors in existence were completely safe to operate, there would still be unsolved issue of what to do with the waste from generating electricity by means of nuclear energy. Those who claim that they feel comfortable with nuclear energy are, none the less, concerned about waste disposal methods. Seven states, including California, have put the building of nuclear plants on hold until legislators are convinced that there is a safe way to dispose of the radioactive waste from the plants.
In the meantime, pools of liquid waste and piles of solid waste from private industry and governmental bomb production grow. Since 1962, the volume of radioactive waste produced by the nuclear power industry has amounted to about 4,300 cubic meters. By the end of the twentieth century, if production continues at the same rate, there will be 40,000 cubic meters of nuclear waste.
Power plants and bomb-making are not the only sources of waste. Uranium mining and milling operations have dumped 24 million metric tons of radioactive tailing wastes at dumping sites around the nation. At places where uranium is currently milled, there is another 100 million metric tons of tailings. Uranium tailings are solid materials in the slurry (or watery mixture) of depleted ore-bearing rock, chemicals, and liquids that result from milling. Usually, the slurry is piped to holding ponds. When a uranium mill goes out of business, the ponds are left to
evaporate
, uncovering piles of dried tailings. Uncovered piles of tailings give off radioactive radon gas. Once in the air, the gas finds its way into the water supply and the food chain. Consequently, many nuclear experts agree that uranium mill tailings may be more dangerous than high-level radioactive wastes from reactors and bombs.
单选题
It can be inferred from the passage that the most dangerous by-product of uranium mining and milling is ______.
【正确答案】
C
【答案解析】[解析] 推断题。选项中的内容在文中均有提及,但是从危害性上讲,选项A、B、D都没有直接说到它们的害处,而文中第三段讲到Uncovered piles of tailings give off radioactive radon gas. Once in the air, the gas finds its way into the water supply and the food chain. 故可推断出这种放射性气体才是最有害的。故选项C正确。
单选题
The central idea of the passage is to point out potential problems regarding __
【正确答案】
D
【答案解析】[解析] 主旨题。作者在短文第一句就指出了主题:The most pressing nuclear energy issue is the disposal of nuclear waste. 关键词是“核废料”nuclear waste。故选项D正确。
单选题
According to the passage, all of the following are sources of radioactive waste EXCEPT ______.
【正确答案】
B
【答案解析】[解析] 细节题。作者在第三段提到核废料的来源有:Power plants and bomb-making are not the only sources of waste. Uranium mining and milling operations...显然没有提到B选项的内容,故选B。
单选题
According to the passage, the term "uranium mine tailings" refers to ______.
【正确答案】
C
【答案解析】[解析] 词汇题。短文第三段中间提到Uranium tailings are solid materials in the slurry (or watery mixture) of depleted ore-bearing rock, chemicals, and liquids that result from milling. 意思是:铀废料是加工所产生的由废弃的矿岩石、化学物和液体所组成的流质混合物中的固体物质。tailings在这里指“残渣,废料”。故选项C正确。
单选题
The word "evaporate" (Line 7, Para.3) means ______.
【正确答案】
A
【答案解析】[解析] 词汇题。根据上下文来推测词义。根据the ponds are left to evaporate, uncovering piles of dried tailings可判断出由于池塘里的液体蒸发没有了,废料才露了出来。故选项A正确。