阅读理解。

     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 100 years ago. Because more people live l
onger, there are more people around at any given time. In fact, it is a decrease in death rates, not an
increase in birthrates, 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(饥荒), infants might be allowed to die because they could not survive if their parents starved,
but if the parents survived they could have another child. In most contemporary(当代的) societies,
people feel a moral responsibility 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 America 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 (衰老的) or too weak and ill 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 (疗养的) hospitals have been built. These are often profit-making
organizations, although some are sponsored(主办) by religious and other nonprofit groups. While a
few of these institutions are good, most of them are simply “dumping (倒垃圾的) grounds” for the
dying in which “care” is given by poorly paid, overworked, and under-skilled personnel.?

1．The author believes that the population explosion results from       

A．an increase in birthrates
B．the industrial development?
C．a decrease in death rates
D.human beings' cultural advances

2．According to the passage, which of the following statements about the old people in America is
      TRUE?

A．Many of them live on social security money which is hardly enough.?
B．Minority of them remain in a state of near poverty after their
      retirement.
C．When they reach a certain age, compulsory retirement is necessary and
       beneficial.
D. With the growing inflation（通货膨胀）, they must suffer more from unbearable burdens than ever?

3．The underlined phrase “this need” in Paragraph 3 refers to        ?

A．prolonging the dying old people's lives?
B．reducing the problems caused by the retired people?
C．making profits through caring for the sick or weak people?
D．taking care of the sick or weak people?

4．Which best describes the author's attitude toward most of the nursing homes, and convalescent
      hospitals??
A．Sympathetic.    
B．Approving.
C．Optimistic.    
D．Critical.