没有（）的作用创业能力纵向结构各层次就不可能形成和发挥作用。A．观察力 B．注意力

International free trade occurs when there are no barriers to trade. Countries can get a lot of benefits from free trade. (31) , all countries choose to adopt protection policies to some extent In this essay, I will give (32) of the arguments in favour of world free trade, describe the methods for the trade protection policies (33) countries erect to protect domestic industries and give the arguments which can be put (34) to justify protectionist policies.
Tariffs are taxes on (35) products. Sometimes, tariffs are known (36) imports duties and customs duties. They can be used (37) raise revenue. But, they are usually used to (38) imports and also to help domestic producers. The effect of imposing (39) tariff is to raise price for domestic consumers, and some consumers will switch consumption (40) imported goods to domestically produced substitutes. (41) are two types of tariffs. One is percentage taxes, it is based on
percentage of value of goods. (42) one is specific (fixed sum taxes), it is based on a fixed tax (43) unit or weight. Quota is a limit on the supply of goods or services. It can be imposed on exports. The domestic market share will increase because of (44) a limit on the quantity of imported goods. However, the price of protected goods will also rise because a quota is to reduce supply. Voluntary export restraint or restriction (45) similar to a quota, but this time the limit on imports arises from a voluntary agreement (46) the exporting and importing countries. For example, the UK had an agreement with Japanese car (47) that they should not take (48) than 10 percent of the UK car market. Exchange control means that a government control on foreign currency controls importers access to foreign currency. This is a (49) which was used by a number of European countries, (50) the UK, in the 1960s and 1970s and is still found in some developing countries.

指出下列各句所用的修辞手法。   

（1）生命像向东流的一江春水，他从最高处发源。（    ）   

（2）她多么辽阔，多么伟大！多么光明，又多么黑暗！（    ）   

（3）他便伸出嫩叶来吸收空气，承受日光，在雨中吟唱，在风中跳舞。（    ）

已调节好的托盘天平测量铜块的质量，当天平平衡时，右盘中砝码有50g、20g 、10g各1个，游码的位置如图所示，则该铜块的质量是_________g。若把上述实验移到山顶上进行，测得的该铜块的质量将________（填“变大”“不变”或“变小”）

不是药物利用研究中的定量研究内容的是（）

A.随机抽样，对药物的临床效果、销售价格和消费结构及其社会、经济效益作出评价

B.对药物利用的质量、必要性和恰当性进行评价，从而提供一个可供对照的、明确的、超前决策性的技术规范

C.用作疾病流行的一个最原始性的标志

D.监测某些指定性药物或常规性药物的作用、有效性

E.规划药物的进口、生产、销售以及药物的费用，社会保险及国家防疫保健的财政补贴标准等

可控硅的阳极是输入端，阴极是输出端，控制极也就是控制端，控制极应接（）电压。

A.正向

B.反向

C.都可