模拟信号转变为数字信号需要经过以下三个过程（）；（）和编码。

钢筋混凝土构件中混凝土主要承受压力。( )

男，30岁，油漆工人，因面色苍白，心悸，气短，伴下肢反复淤点2年就诊，体检重度贫血貌，心率120次／分，肝脾未及，红细胞2．0×10¹²／L，血红蛋白6％／L，白细胞3．0×10⁹／L，血小板35×10⁹／L，网织红细胞0．4％，MCV95fl。

下列哪项辅助检查对诊断最有帮助（）

A.Hain试验

B.叶酸、维生素B₁₂测定

C.心脏B超

D.肝、脾B超

E.骨髓检查

根据检疫机构签发的产地证书是进口国海关征收或减免关税的有效凭证( )

阅读表达。

     Work is a very important part of life in the United States. When the early Protestant immigrants (新教徒移

民) came to this country, they brought the idea that work was the way to God and heaven. This attitude, the

Protestant Work Ethic (道德规范), still influences America today. Work is not only important for economic

benefits, the salary, but also for social and psychological need the feeling of doing something for the good of

the society. Americans spend most of their lives working, being productive. For most Americans, their work

defines them: they are what they do. What happens then, when a person can no longer work? Almost all

Americans stop working at age sixty-five or seventy and retire. Because work is such an important part of life

in this culture, retirement can be very difficult. Retirees often feel that they are useless and unproductive. Of

course, _____; but leaving one's job, whatever it is, is a difficult change, even for those who look forward to

retiring. Many retirees do not know how to use their time or they feel lost without their jobs.

     Retirements can also bring financial problems. Many people rely on Social Security checks every month.

During their working years, employees contribute a certain percentage of their salaries to the government.

Each employer also gives a certain percentage to the government. When people retire, they receive this money

as income. These checks do not provide enough money to live on, however, because prices are increasing

very rapidly. Senior citizens, those over sixty-five, have to have savings in the bank or other retirement plans

to make ends meet. The rate of inflation (通货膨胀)is forcing prices higher each year. Social Security checks

alone cannot cover these growing expenses. The government offers some assistance, medicare and welfare,

but many senior citizens have to change their life styles after retirement. They have top spend carefully to be

sure that they can afford to buy food, fuel and other necessities.

     American society is only beginning to be concerned about the special physical and emotional needs of its

senior citizens. The government is taking steps to ease the problem of limited income. They are building new

housing,offering discounts in stores and museums and on buses, and providing other services such as free

courses, food service, and help with housework.

1. What's the general idea of this passage? (Please answer within 10 words.)

    ______________________________________________________________________________________

2. Translate the underlined sentence in the first paragraph into Chinese.

    ______________________________________________________________________________________

3. Please fill in the blank with proper words or phrases. (Please answer within lo words.)

    ______________________________________________________________________________________

4. Which sentence in the passage is the closet in meaning to the following sentence? Retirees will have many

    economic difficulties after retiring.

   ______________________________________________________________________________________

5. What other suggestions would you give to the govemment to take steps to ease the problems of limited

    income of the senior citizens? (Please answer within 30 words.) 

   ______________________________________________________________________________________

在进行了任何C++流的操作后，都可以用C++流的有关成员函数检测流的状态，其中只能用于检测输入操作的函数的函数名是

A．fail

B．eof

C．bad

D．good