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问题 多项选择题

在完全垄断市场上，企业可以通过调整( )来实现利润最大化。

A．产量

B．成本

C．供应量

D．销售量

E．价格

答案

参考答案：A,E

解析： 在完全垄断市场上，企业不仅可以通过调整产量，而且还可以通过调整价格来实现利润最大化。

单项选择题

Believe it or not，optical illusion can cut highway crashes.
Japan is a case in point．It has reduced automobile crashes on some roads by Rearly 75 percent using a simple optical illusion．Butst．ripes,called chevrons(人字形)，painted on ther rads make drivers think that they are driving faster than they really are，and thus drivers slow down.
Now the American Automobile Association Foundation for Traffic Safety in Washington D．C. is planning t。repeat Japan’s success．Starting next year，the foundati。n will paint cheyrons and。ther pattems of stripes on selected roads around the country to test how well the patterns reduce highway erashes．
Excessive(too great)speed plays a major role in as much as one fifth of all fatal traffic accidents， according to the foundation．To help reduce those accidents，the foundation will conduct its tests in areas where speed-related hazards(danger)are the greatest curves，exit slopes，traffic circles，and bridges．
Some studies suggest that straight，horizontal bars painted across roads can initially cut the average speed of drivers in half．However,traffic。ften returns to full speed within months as driVers become used to seeing the painted bars．
Chevrons，scientists say，not only give drivers the impression that they are driving faster than they reallv are but als0 make a lane appear to be narrower．The result is a longer lasting reduction in highway speed and the number of traffic accidents．

The advantage of chevrons over straight, horizontal bars is that the former______.

A. can keep drivers awake

B. can cut road accidents in half
C. will look more attractive

D. will have a longer effect on drivers
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问答题

能源是人类生存和社会繁荣的重要物质基础之一，为了保护环境并实现经济的持续增长，开发和利用新能源是人类必然的选择。

（1）我市徐闻县毗邻琼州海峡，风力资源极为丰富，随着广东粤能（集团）有限公司风力发电项目的建设，徐闻将成为广东省最大的风力发电基地。该电站规划前期年发电量约为4×108kw．h，这相当于完全燃烧______kg煤所放出的能量（煤的热值为3.0×107J／kg）。

（2）风力发电时，它是将风能转化为电能，该能源属于___________（填“可”或“不可”）再生能源；与火力发电相比，风力发电的优点是___________________________。

（3）某研究小组为了探究风力发电的影响因素，设计了一种测定风力的装置，其原理如图1所示。金属迎风板与用绝缘材料制成的轻弹簧的一端N相接，一起套在电阻均匀的光滑金属杆上。电路中左端导线与金属杆的M端相连，右端导线接在迎风板的N点上，并可随迎风板在金属杆上滑动，导线与金属杆接触良好，电源两端电压不变。现给你一只电压表，请把它接入此装置的电路上，使电压表的示数随风力的增大而增大。则此电压表应并联在图中什么位置_______________。

（4）图2为近两个多世纪以来，人类能源消耗情况的示意图。请你分析图中数据，谈谈你最担忧的问题（谈两点即可）_____________________________、___________________________；并提出一条日常生活中节约能源的措施______________________________。

                                               图1                                                     图2
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