单项选择题 A1/A2型题：飞行员膳食中脂肪提供能量的适宜比例是（）。 A.25%～30% B.10%～15%

题型：单项选择题 A1/A2型题

If you give something to someone for free, will that person value it and use it? Development experts have debated this question for decades. Some think the act of paying causes people to value something and use it more.

Selling necessary health treatments, others argue, may deny them to the people who need them the most.

Consider, for example, chemically treated bed nets, which kill mosquitoes anti protect people against malaria(疟疾)while they are sleeping. William Easterly, an economist at New York University, believes this is one example of development having gone wrong. In a recent book, Professor Easterly suggests bed nets given free in Africa are often used for the wrong purpose. Yet, the World Health Organization (WHO) recommends bed nets be given out free and used by whole communities. The success of a large free bed net campaign in Kenya led the WHO to announce this recommendation

This debate will likely influence social programs in the developing world. Many non-governmental organizations support the creation of self-supporting programs in poor countries. Goods and services are sold for a price to help these programs survive.

According to Rachel Glenerster, who runs a research lab doing development and poverty studies at the Massachusetts Institute of Technology, her several studies have proven that small price changes have a big influence on the number of people who use a product. A price change will reduce the total amount of use of the product as well, she says. She has also found no evidence that the very act of paying for something changes how people use it.

As for a particular product among special populations, some development experts argue that pricing is useful. When it comes to bed nets, Miss Glenerster says research shows no evidence of this. People are just as likely to use a bed net whether they paid for it or not.

小题1: The debate among experts focuses on .

A．a special use of bed nets in Africa

B．the use of assistance-related products

C．the importance of social programs for the poor

D．a popular way to help the poor小题2: According to some experts, certain health treatments .

A．can only be sold to the rich

B．should be completely free

C．are too expensive

D．are not needed by the poor小题3:What can be inferred from Paragraph 2?

A．The WHO's advice may not be always practical.

B．Many Africans don't know the function of bed nets.

C．The case of Kenya is doubtful.

D．Bed nets given to Africans are poor in quality.小题4: What may be the possible change in the social program according to the third paragraph?

A．Some of them may become financially independent.

B．Many of them will not be organized by the government.

C．Some of them will go to developed countries.

D．Most of them will be free of charge.

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飞行员膳食中脂肪提供能量的适宜比例是（）。 A.25%～30% B.10%～15%

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