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问题 单项选择题

下列各项中，不属于西方税收效应分析理论的局限性有（）。

A、基本假设过于严格，其中完全竞争市场的假定基本是不存在的

B、没有将现实中各不相同的企业行为区别对待，最重要的是不能及时地将影响企业行为的其他因素诸如信息化、边际成本递减、内生增长等因素考虑在原模型之中

C、没有将具体的税收制度模型化，分析线条过于宽泛，即缺少针对具体的税收制度的分析和研究

D、经济研究人员的统计数据不能反映基本的情况

答案

参考答案：D

单项选择题

关于排卵机制下列不正确的是

A．促性腺释放激素的作用
B．LH/FSH出现高峰
C．E3的正反馈作用
D．与组胺增加有关
E．前列腺素增加
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单项选择题

When a disease of epidemic proportions threatens the public, scientists immediately get to work, trying to locate the source of affliction and find ways to combat. Vaccination is one of the effective ways to protect the (1) population of a region or country which may be (2) grave risk. The process of vaccination allows the patient’s body to (3) immunity to the virus or disease so that, if it is encountered, one can fight it (4) naturally. To accomplish this, a small weak or dead (5) of the disease is actually injected into the patient in a controlled environment, (6) his body’s immune system can learn to fight the invader (7) . Information (8) how to penetrate the disease’s defenses is (9) to all elements of the patient’s immune system in a process that occurs naturally, in which genetic information is passed from cell to cell. This makes sure that (10) the patient later come into contact with the real problem, his body is well equipped and trained to (11) with it, having already done so before.

There are, however, dangers (12) in the process. (13) , even the weakened version of the disease contained in the vaccine proves (14) much for the body to handle, resulting in the immune system (15) , and, therefore, the patient’s death. Such is the case of the smallpox vaccine, (16) to eradicate the smallpox epidemic that nearly (17) the whole Native American population and killed massive numbers of settlers. (18) 1 in 10,000 people who receive the vaccine (19) the smallpox disease from the vaccine itself and dies from it. Consequently, the process, which is truly a (20) , may indeed hide some hidden curses.

16（）

A.invented

B.discovered

C.investigated

D.designed
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