问题 单项选择题

近几十年来,人们发明了各种各样的药物来毒杀老鼠。可是人们发现,在一些老鼠经常出入的地方放置老鼠药的方法越来越没有效果,人们将药物添加到对于老鼠来说那么美味的食物之中,老鼠都会对这些送来的“美味”置之不理。根据这一现象,得到的可能解释是:老鼠的嗅觉异常灵敏,它们能从任何复杂的气味中辨别出对它们有害的物质。

下列哪项能最强有力地表明上文中最后一个解释是错误的?()

A.老鼠很少去那些曾经放置过老鼠药的地方活动

B.老鼠在进食之前对任何食物进行取样并品尝其中是否有有毒物质

C.科学家经过一系列试验,证明有的老鼠对于一些药物已经产生抗药性

D.将没有添加任何药物的粮食放在先前放置过药物的地方,老鼠也不会去动这些食物

答案

参考答案:D

解析:

题干给出的命题是,将含药物食物放在老鼠经常出入的地方,老鼠不会动这些食物,从而判断老鼠能闻出药物。D项说明,即使放的是没有药物的食物,老鼠依然不会碰,说明老鼠并不能闻出食物中是否有药物,而是因为别的原因导致老鼠不去碰这些食物,从而有力地削弱了题干。

单项选择题

If you think you can make the planet better by clever shopping, think again. You might make it worse.

You probably go shopping several times a month, providing yourself with lots of opportunities to express your opinions. If you are worried about the environment, you might buy organic food; if you want to help poor farmers, you can do your bit by buying Fairtrade products; or you can express a dislike of evil multinational companies and rampant globalization by buying only local produce. And the best bit is that shopping, unlike voting, is fun; so you can do good and enjoy yourself at the same time.

Sadly, it’s not that easy. (41) . People who want to make the world a better place cannot do so by shifting their shopping habits: transforming the planet requires duller disciplines, like politics.

Organic food, which is grown without man-made pesticides and fertilisers, is generally assumed to be more environmentally friendly than conventional intensive farming, which is heavily reliant on chemical inputs. But it all depends on what you mean by "environmentally friendly". Farming is inherently bad for the environment: since humans took it up around 11 000 years ago, the result has been deforestation on a massive scale.

(42) . Organic methods, which rely on crop rotation, manure and compost in place of fertiliser, are far less intensive. So producing the world’s current agricultural output organically would require several times as much land as is currently cultivated. There wouldn’t be much room left for the rainforest.

Fairtrade food is designed to raise poor farmers’ incomes. It is sold at a higher price than ordinary food, with a subsidy passed back to the farmer. But prices of agricultural commodities are low because of overproduction, (43) .

Surely the case for local food, produced as close as possible to the consumer in order to minimise "food miles" and, by extension, carbon emissions, is clear Surprisingly, it is not. A study of Britain’s food system found that nearly half of food-vehicle miles (i. e. , miles travelled by vehicles carrying food) were driven by cars going to and from the shops. Most people live closer to a supermarket than a farmer’s market, so more local food could mean more food-vehicle miles. Moving food around in big, carefully packed lorries, as supermarkets do, may in fact be the most efficient way to transport the stuff

What’s more, once the energy used in production as well as transport is taken into account, local food may turn out to be even less green. (44) . And the local-food movement’s aims, of course, contradict those of the Fairtrade movement, by discouraging rich-country consumers from buying poor-country produce. But since the local-food movement looks suspiciously like old-fashioned protectionism masquerading as concern for the environment, helping poor countries is presumably not the point.

(45) . The problems lie in the means, not the ends. The best thing about the spread of the ethical-food movement is that it offers grounds for hope. It sends a signal that there is an enormous appetite for change and widespread frustration that governments are not doing enough to preserve the environment, reform world trade or encourage development.

44()

A.The aims of much of the ethical-food movement--to protect the environment, to encourage development and to redress the distortions in global trade--are admirable.

B.By maintaining the price, the Fairtrade system encourages farmers to produce more of these commodities rather than diversifying into other crops and so depresses prices--thus achieving, for most farmers, exactly the opposite of what the initiative is intended to do.

C.Proper free trade would be by far the best way to help,poor farmers. Taxing carbon would price the cost of emissions into the price of goods, and retailers would then have an incentive to source locally if it saved energy.

D.There are good reasons to doubt the claims made about three of the most popular varieties of "ethical" food: organic food, Fairtrade food and local food.

E.But following the "green revolution" of the 1960s greater use of chemical fertiliser has tripled grain yields with very little increase in the area of land under cultivation.

F.And since only a small fraction of the mark-up on Fairtrade foods actually goes to the farmer--most goes to the retailer-the system gives rich consumers an inflated impression of their largesse and makes alleviating poverty seem too easy.

G.Producing lamb in New Zealand and shipping it to Britain uses less energy than producing British lamb, because fanning in New Zealand is less energy-intensive.

多项选择题