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问题 填空题

观察两幅图回答问题：

（1）简单的说雪是由水蒸气               （物态变化）而成的，该过程需要              （吸热/放热）．

（2）雪雕与冰雕不但会熔化还会升华，那么在0℃以下的东北极寒的天气里它们是以               （熔化/升华）方式变小．

答案

（1）凝华；吸热

（2）升华

单项选择题

Which one of the following is least accurate with regard to money serving as a medium of exchange Without money to serve as a medium of exchange:（）

A. people’s standard of living would probably decline.

B. people would continue to enjoy their current standard of living and countries would become more self-sufficient in production of goods and services.

C. the transaction cost of exchange would increase.
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单项选择题

粗死亡率这一指标的高低（）。

A.受人口年龄构成影响不大

B.受人口年龄构成影响大

C.能用来评价一个国家的卫生文化水平

D.可以精确地反映人口的死亡水平

E.可反映某人群主要的死亡原因
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