下列关于精馏塔的完好标准的说法正确的是（）。A．设备各参数没有任何波动 B．塔体构件

定义在（﹣∞，+∞）上的偶函数f（x）满足f（x+1）=﹣f（x），且f（x）在[﹣1，0]上是增函数，下面五个关于f（x）的命题中：

①f（x）是周期函数；

②f（x）图象关于x=1对称；

③f（x）在[0，1]上是增函数；

④f（x）在[1，2]上为减函数；

⑤f（2）=f（0），

正确命题的个数是　    [     ]

A．1个

B．2个

C．3个

D．4个

赵某，女。46岁。1979年6月25日初诊。主诉：眩晕、耳鸣7年，加重3个月。患者自1972年患高血压病以来，常发生头晕头昏耳鸣，近3个月未加重。伴有失眠多梦，时觉心悸，两目干燥，视物不清，腰困无力。后项部板硬不灵活，面有烘热感，心中烦闷。月经正常。平时血压高时服降压片。本次虽服上药血压有所下降，但症状不消。故来就诊。检查：血压：160／96mmHg。舌红少苔，脉细。

该病的中医诊断是（）

A.头痛

B.胸痹

C.中风

D.眩晕

E.以上都不是

简述认知功能发育的顺序。

The central problem of economics is to satisfy the people’s and nation’s wants. The problem we are faced with is that our (1) , here identified as money, are (2) . The only way we can resolve our (3) is to make choices. After looking at our resources, we must examine our list of (4) and identify the things we need (5) , those we can postpone, and (6) we cannot afford. As individuals, we face the central problem involved in economics — deciding just how to allocate our limited resources to provide ourselves with the greatest (7) of our wants.
Nations face the same problem. As a country’s population (8) , the need for more goods and services grows (9) . Resources necessary to production may increase, but there are (10) enough resources to satisfy the total desires of a (11) . Whether the budget meeting is taking place in the family living-room, in the conference room of the corporation (12) of directors, or in the chamber of the House of Representatives in Washington, the basic problem still exists. We need to find (13) of allocating limited resources in order to satisfy unlimited wants.
A short time ago, economists divided goods into two categories, free and economic. The former, like air and water, were in (14) abundance that economists had no concern about (15) of scarcity and what to do about it. Today many of these "free goods" are in (16) very expensive to use. Pollution has made clean air and water expensive for producers who have to filter their waste products, for consumers who ultimately pay for the producers’ extra costs, and (17) tax-payers who pay for the government’s involvement in cleaning the environment.
In the 1990s, almost all goods are (18) . Only by effort and money can they be (19) in the form people wish.
Meeting the needs of people and the demands from resources available leads to the basic activity of production. In trying to (20) unlimited wants from limited economic goods, production leads to new problems in economics.

对达尔文自然选择学说的正确评价是( )。

A．它能正确解释生物界的多样性和适应性
B．它能正确解释遗传和变异的本质
C．它能正确解释生物界的多样性和适应性，但没有阐明遗传性和变异的本质
D．它能解释自然选择作用，不能阐明生物界的多样性