某高校十个系的学生信息放在一张基本表里，下列措施可使各系的管理员只能读取本系的学生信

随着气温的攀升，空调销售旺季即将到来，国美电器发布《2011年空调市场消费趋势报告》（以下简称《白皮书》），对市场普遍预期的空调涨价有自己的看法。《白皮书》认为，由于市场竞争激烈，空调难涨价。“原材料一涨价，产品就涨价，这其实忽略了渠道商对价格缓冲和平抑的功能。”国美电器副总裁李俊涛坦言，不认同原材料价格上涨将引发空调价格上涨的推断，致使2011年国内空调生产企业仍然出现了新一轮的降价大战，市场竞争日趋激烈，有不少企业可能面临倒闭。

用所学的《经济生活》知识回答：

（1）生产资料价格上涨的原因是什么？

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（2）为什么生产资料价格的上涨没有引起空调价格的上涨？

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Today’s lecture is about the mass (1) of the world’s population. There are two major (2) why people are moving to cities. The first reason is (3) . People are moving to the cities because that’s where they can find (4) and earn money. The second reason for the move to cities has to do with (5) of life issues: comfort and (6) . Cities often offer better (7) . And then for many, city life is just more (8) . An interesting consequence of urbanization is that the average (9) of people in the countryside is increasing, while that of the cities is (10) .
Three key (11) can be identified in our cities. First of all, they’re getting bigger. Most cities are bigger now than ever before. Cities are also changing shape. They’re getting (12) , because land is getting more and more expensive. (13) have become a symbol of modern cities.
Cities are also changing shape in other ways. The (14) Model and the (15) Nuclei Model are probably more typical of the cities we know today. They show the urban (16) that’s occurring in contemporary cities.
The third change is that our cities are breaking up into (17) communities, often by (18) group or (19) level. This often means that people stay within their community and do not come into contact with others from different (20) .

影响机床部件刚度的因素有哪些？

职业指导的内涵大体有“选择论”“服务论”“教育过程论”三类。( )

在金属矿山应用最多的是（）凿岩机。

A.电动

B.液压

C.风动