问题
单项选择题
胃腺粘液细胞可（）
A．分泌胃蛋白酶原和凝乳酶原
B．分泌盐酸和抗贫血因子
C．分泌碱性粘液，保护胃粘膜
D．分泌胃泌素
E．分泌降钙素
答案
参考答案：C
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胃腺粘液细胞可（）
A．分泌胃蛋白酶原和凝乳酶原
B．分泌盐酸和抗贫血因子
C．分泌碱性粘液，保护胃粘膜
D．分泌胃泌素
E．分泌降钙素
参考答案：C
Passage Two
| Conventional wisdom has it that concern for the environment is a luxury only the rich world can afford; that only people whose basic needs for food and shelter have been met can start worrying about the health of the planet. This survey will argue that developing countries, too, should be thinking about the environment. True, in the rich countries a p environmental movement did not emerge until long after they had become industrialized, a stage that many developing countries have yet to reach. And true, many of the developed world’s environmental concerns have little to do with immediate threats to its inhabitants’ well-being. People worry about whether carbon-dioxide emissions might lead to a warmer climate next century, or whether genetically engineered crops might have unforeseen consequences for the ecosystem. That is why, when rich world environmentalists’ campaign against pollution in poor countries, they are often accused of naivety. Such countries, the critics say, have more pressing concerns, such as getting their people out of poverty. But the environmental problems that developing countries should worry about are different from those that western pundits have fashionable arguments over. They are not about potential problems in the next century, but about indisputable harm being caused today by, above all, contaminated water and polluted air. The survey will argue that, contrary to conventional wisdom, solving such problems need not hurt economic growth; indeed dealing with them now will generally be cheaper than leaving them to cause further harm. In most developing countries pollution seems to be getting worse, not better. Most big cities in Latin America, for example, are suffering rising levels of air pollution. Populations in these countries are growing so fast that improvements in water supply have failed to keep up with the number of extra people. Worldwide, about a billion people still have no access to clean water, and water contaminated by sewage is estimated to kill some 2 million children every year. Throughout Latin America, Asia, Africa, forests are disappearing, causing not just long-term concern about climate change but also immediate economic damage. Forest fires in Indonesia in 1997 produced a huge blanket of smog that enveloped much of South-East Asia and kept the tourists away. It could happen again, and probably will. Recent research suggests that pollution in developing countries is far more than a minor irritation: it imposes a heavy economic cost. A World Bank study put the cost of air and water pollution in China at $ 54 billion a year, equivalent to an astonishing 8% of the country’s GDP. Another study estimated the health costs of air pollution in Jakarta and Bangkok in the early 1990s at around 10% of these cities’ income. These are no more than educated guesses, but whichever way the sums are done, the cost is not negligible. |
It is conventionally thought that ______.
A．only rich countries can afford to care about environmental problems
B．developing countries should also be thinking about the environment
C．environmental problems exist only in the rich world
D．rich countries have not paid enough attention to the health of the planet