科研用蝴蝶标本

-3-（-5）=________。

制定和贯彻执行行政法的基本准则是( )。

A．宪法

B．法律

C．行政法规

D．规章

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 longer,

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, infants might be allowed to die because they could not survive if their parents starved, where

as if the parents survived they could have another child. In most contemporary (当代的)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 illnesses than

young or middleaged 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 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. It can be inferred from the passage that in hunting and gathering cultures  ________.

A. it was a moral responsibility for the families to keep alive the aged people who could not work

B. the survival of infants was less important than that of their parents in times of starvation

C. old people were given the task of imparting the cultural wisdom of the tribe to new generations

D. death was celebrated as a time of rejoicing for an individual freed of the hardships of life

3. According to the passage, which of the following statements about the old people in the United States

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, they must suffer more from unbearable burdens than ever.

4. The 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

5. Which of the following BEST describes the author's attitude toward most of the nursing homes and

convalescent hospitals?

A. Sympathetic.  

B. Approving.

C. Optimistic.  

D. Critical.

脂肪酸在体内氧化分解时，最为基本和重要的方式是______

A．α-氧化分解
B．β-氧化分解
C．γ-氧化分解
D．δ-氧化分解
E．ω-氧化分解

节流调速回路所采用的主要液压元件是（）。

A.变量泵

B.调速阀

C.节流阀

D.换向阀