题目内容：

Who takes care of the elderly in the United States today? Many people wrongly believe that when people reach old age, their families place them in nursing homes. They are left there in the hands of strangers for the rest of their lives. Their grown-up children visit them only occasionally, but more often, they do not have any regular visitors. Actually this is not true. In fact, family members provide over 80 percent of the care that elderly people need.

Prof. Samuel Preston, a sociologist at the University of Pennsylvania, studied how the American family is changing. He reported that by the time the average American couple reaches 40 years of age, they have more parents than children. This statistic (统计) shows the change in life-styles and responsibilities of aging Americans. The average middle-aged couple can look forward to caring for elderly parents some time after their own children have grown up. Moreover, because people today live longer after an illness than people did years ago, family members must provide long-term care. These facts also mean that after care-givers provide for their elderly parents, who will eventually die, they will be old and may require care too. When they do, their spouses (配偶, 指夫或妻) will probably take care of them.

Because Americans are living longer than ever, more psychologists and social workers have begun to study care-giving to improve care of the elderly. They have found that all caregivers share a common characteristic: all caregivers believe that they are the best person for the job, for different reasons. One caregiver said that she had always been close to her mother. Another was the oldest child. In other words, they all felt that they could do the job better than anyone else. Social workers interviewed caregivers to find out why they took on the responsibility of caring for an elderly, dependent relative. They discovered three basic reasons. Many caregivers believed that they had the responsibility to help their relatives. Some stated that helping others made them feel more useful. Others hoped that by helping someone now, they would deserve care when they became old and dependent.

48. It can be inferred that a middle-aged couple in the US _______.

A. spend more time with their children than with their parents

B. depend on their children’s assistance in caring for the elderly

C. don’t pay more attention to their children than to their parents

D. spend more time taking care of their parents than before

49. The most common characteristic of caregivers is ______.

A. they all have professional qualifications in care-giving

B. they all believe themselves to be the best caregiver

C. they are the eldest child in the family

D. they are close to their parents

50. Which of the following is NOT a basic reason for care-giving?

A. Respect from other members of the family.

B. Prepayment for the care they will get in old age.

C. A feeling of being needed and helpful.

D. A strong sense of duty to the elderly.

51. What is the main idea of this passage?

A. Most old people in the US are living a happy life.

B. Most old people in the US live longer today after an illness than people did years ago.

C. Most elderly people in the US are taken care of by their families, who often find the experience satisfying.

D. Most elderly people in the US prefer living with their families to living nursing houses.