显微镜是常用的探究器具,帮助我们观察肉眼无法观察到的细微结构;在它的结构中,与放

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问题:

显微镜是常用的探究器具,帮助我们观察肉眼无法观察到的细微结构;在它的结构中,与放大有关的部件是______和______.

考点:显微镜的构造和使用
题型:填空题

存在于多聚核苷酸的骨架成分是()

A.碱基与磷酸

B.碱基与戊糖

C.碱基与碱基

D.戊糖与磷酸

E.葡萄糖与磷酸

题型:填空题

体内脱氧核苷酸是由下列哪类物质直接还原生成的

A.核糖核苷
B.一磷酸核苷
C.二磷酸核苷
D.三磷酸核苷

题型:填空题

弱化子(attenuator)

题型:填空题

Why must we pay taxes The answer is that the government needs money for many things, for example, to pay its soldiers, sailors and airmen, to build roads, bridges, offices, schools, etc, and to buy goods from abroad ; and only the people of the country can supply the money. One of the most important taxes is income-tax which a person pays according to the amount of his income, whether he is a merchant, a doctor, a lawyer, a shopkeeper, a miner or anything else. This is called a "direct" tax, because it is paid in money directly to the government. Another tax is paid on goods such as watches, jewelry, new clothes, tobacco, wine, etc, when they are brought into a country. Such a tax is paid as part of the price of these goods if they are late sold in shops. We call it "indirect" tax, because it is paid indirectly through the shopkeepers. People usually complain about having to pay taxes, but they forget that the money is spent on things that they and their families need. We need policemen to catch thieves, to see that men obey the laws, to direct traffic, etc, and they must be paid what they earn; children need education, and there must be schools and teachers; we want our streets to be kept clean, and the wages of men who do this kind of work have to be paid. Above all, the country must always be ready to defend itself against attacking enemies, and we can’t have an army without paying for it. Besides, if a country wants to develop, there are many other things to do... Taxes, therefore, cannot be avoided. We buy our food and clothes and pay for our amusements; but, there are several things that the State finds the money for, and that is necessary for us if our society is to continue. We have no real reason to complain, therefore, when we are asked to supply money to be spent for the good of ourselves and for our fellow-citizens.

Title: (46)
Governments need (47)
for many things to do
  • a. (48) its soldiers, sailors and airmen
  • b. (49) roads, bridges, offices, schools, etc
  • c. (50) goods from abroad
Kinds of taxes and tax-payers a. (51) , which is paid by people whose income is over a certain amountb. (52) , which is paid through the shopkeepers
The function of tax Guarantee the (53) and the (54) of a country
(55) Taxes can not be avoided

题型:填空题

试对汇率决定理论中货币论的主要理论模型分别加以论述。

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