单项选择题

The first question is how hest to separate clean element—glass containers, plastics, and some paper and metal containers that is relatively clean when discarded-from mixed refuse (废料, 垃圾). This clean element is the main target for Britain’s recyclers. The method of collection is important because manufacturers will not reuse collected material unless it is clean and available in sufficient quantities. A bewildering assortment(混合) of different collection schemes operates in the rest of Europe, and pilot schemes are now under way in many British cities.
Recycling is possible only when

A. it is monitored by the government.
B. different collection schemes operate.
C. there is enough clean material.
D. there is a small amount of clean material.
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单项选择题
In recent years, backpacks have begun sporting outside pockets that are, not coincidentally, the perfect size for an iPod. Handbags routinely feature cell-phone compartments. And now, from practical to modem, the fashion industry is taking a cue from these gadgets, integrating their technologies into the fabrics rather than merely providing storage for them. From where do fashion designers get the idea of integrating technology into fabrics according to the passage
A. The outside pockets for iPods on backpacks.
B. The cell-phone compartments on handbags.
C. Costumes from science, fictional thrillers.
D. The small gadgets of modem technologies.
单项选择题
Spindler’s team fed three mice a normal diet for their whole lives, and fed another three on half-rations. Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old-equivalent to about 70 human years. The researchers checked the activity of 11,000 genes from the mouse livers,and found that 46 changed with age in the normally fed mice. The changes were associated with things like inflammation and free production-probably bad news for mouse health. In the mice that had dieted all their lives, 27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 per cent of these gene changes. The researchers found that ______ genes changed with age in the mice that had dieted all their lives.
A. 46
B. 27
C. 19
D. 32
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