已知某选厂精矿中37～19μm粒级回收率为80.76％，求该粒级在尾矿中的损失率？

Some consumer researchers distinguish_____(1) "rational" motives and "emotional" (or "non-rational") motives. They use the term "rationality"_____(2) the traditional economic sense that assumes_____(3) consumers behave rationally when they carefully consider all alternatives_____(4) choose those that give them the greatest utility (i.e., satisfaction). _____(5) a marketing context, the term "rationality" implies that the consumer selects goods based_____(6) totally objective criteria, such_____(7) size, weight, price, and so on. "Emotional" motives imply the selection of goods____(8) to personal or subjective criteria — the desire_____(9) individuality, pride, fear, affection or status.The assumption underlying this distinction is____(10) subjective or emotional criteria do not maximize utility or satisfaction. _____ (11), it is reasonable to assume that consumers always attempt to select alternatives that, ____(12) their view, serve to maximize satisfaction. Obviously, the assessment of satisfaction is a very personal process, based_____(13) the individual’’s own needs as_____(14) as on past behavioral, social, and learning experiences. What may appear_____(15) irrational to an outside observer may be perfectly rational ______(16) the context of the consumer’’s own psychological field. For example, a product purchased to enhance one’’s self-image (such as a fragrance) is a perfectly rational form of consumer behavior. ____(17) behavior did not appear rational to the person who undertakes it_____ (18) the time that it is undertaken, obviously he or she would not do it._____(19) the distinction between rational and emotional motives does not appear to be warranted.Some researchers go so far_____(20) to suggest that emphasis_____ (21) "needs" obscures the rational, or conscious, nature of most consumer motivation. They claim that con sumers act consciously____(22) maximize their gains and minimize their losses; that they act not____(23) subconscious drives but from rational preferences,____(24) what they perceive to be_____(25) their own best interests.

阅读下面材料：

研究表明，在未来30年我国将净增约2亿人左右，2033年前后我国人口将达到峰值15亿人左右，我国面临巨大的人口压力。

请回答：

（1）上述材料说明了我国哪一重要国情？

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（2）我国人口现状的基本特点有哪些？

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（3）面对人口问题，我国必须毫不动摇地坚持的基本国策是什么？其目的是什么？

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（4）坚持上述基本国策有何意义？

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骨质疏松症患者在骨量丢失30%以上时，X线才能有阳性所见。以下不是其X线特点的是（）

A.骨皮质变厚

B.骨结构模糊

C.骨小梁减少或消失

D.骨小梁的间隙增宽

E.椎体双凹变形或前缘塌陷呈楔形变

项目评估是根据客户的要求，在可行性研究的基础上，按照一定的目标，对( )权衡各种方案的利弊，向业主提出明确的评估结论。

A．投资项目建设条件的分析

B．可行性研究中项目目的和目标的分析

C．项目可研报告的效益进行分析

D．投资项目的可靠性进行分析判断

建筑限界