单选题
Prolonging human life has increased the size of the human population. Many people alive today would have died of childhood diseases if they had been born a hundred years ago. Because more people live longer, there are more people around at any given time. In fact, it is a decrease in death rates, not an increase in birth rates, that has led to the population explosion.
Prolonging human life has also increased the dependency load. In all societies, people who are disabled or too young or too old to work are dependent on the rest of society to provide for them. In hunting and gathering cultures, old people who could not keep up might be left behind to die. In times of famine, infants might be allowed to die because they could not survive if their parents starved, whereas if the parents survived they could have another child. In most contemporary societies, people feel a moral obligation to keep people alive whether they can work or not. We have a great many people today who live past the age at which they want to work or are able to work; we also have rules which require people to retire at a certain age. Unless these people were able to save money for their retirement, somebody else must support them. In the United States many retired people live on social security checks which are so little that they must live in near poverty. Older people have more illness than young or middle-aged people~ unless they have wealth or private or government insurance, they must often go on welfare if they have a serious illness.
When older people become senile or too weak to care for themselves, they create grave problems for their families. In the past and in some traditional cultures, they would be cared for at home until they died. Today, with most members of a household working or in school, there is often no one at home who can care for a sick or weak person. To meet this need, a great many nursing homes and convalescent hospitals have been built. These are often profit-making organizations, although some are sponsored by religious and other non- profit groups. While a few of these institutions are good, most of them are simply dumping grounds for the dying in which care is given by poorly paid, overworked, and under-skilled personnel.
单选题
What was the cause to the population growth according to the passage?
【正确答案】
D
【答案解析】此题为细节判断题。文章第一段尾句指出：In fact, it is a decrease in death rates, ...that has led to the population explosion.实际上，是低死亡率导致了人口爆炸，所以D项符合题意。
单选题
It can be learned from the passage that in hunting and gathering societies ______.
【正确答案】
A
【答案解析】此题为推理分析题。文章第二段指出：In times of famine, infants might be allowed to die...whereas if the parents survived they could have another child.遇到饥荒时，婴儿的生存权可能被放弃，而如果父母存活下来，他们还可以再生孩子。由此可以推断，在艰难时期，有优先生存权的是父母，A项符合题意。
单选题
According to the passage, which of the following statements about retired people in the United States is true?
【正确答案】
A
【答案解析】此题为推理分析题。文章第二段指出：In the United States many retired people live on social security checks which are so little that they must live in near poverty.许多退休的老人依靠社会福利生活，但这笔钱很少，以至于他们生活在近乎贫困中。由此可见，他们生活艰难，所以A项符合题意。
单选题
In Paragraph 3, the phrase "this need" refers to ______.
【正确答案】
D
【答案解析】此题为语义辨析题。文章最后一段第三句指出：there is often no one at home who can care for a sick or weak person.由此可知this need指代的是照顾病人和老人这一需要，所以D符合题意。
单选题
What is the author"s attitude toward the nursing homes and convalescent hospitals?
【正确答案】
D
【答案解析】此题为作者态度判断题。文章最后指出：While a few of these institu tions are good, most of them are simply dumping grounds for the dying in which care is given by poorly paid, overworked, and under-skilled personnel.大多数这种机构是倾倒濒死之人的垃圾场，由此可见作者对这些机构是批评的，所以D项符合题意。