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问题 选择题

下列关于水的说法不正确的是

A．水是一种常见的溶剂

B．过滤能除去天然水中所有的杂质

C．自然界中的水都是混合物

D．长期饮用蒸馏水不利于人体健康

答案

B  

题目分析：过滤只能除去不溶于水的杂质，水中仍然含有细菌等微生物及可溶性杂质.

多项选择题

下列哪些不适宜施行扁桃体切除术（）。

A.扁桃体周脓肿

B.急性扁桃体炎

C.再生障碍性贫血

D.风湿性心脏病

E.妇女月经期
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单项选择题

Until recently, most population growth has occurred in relatively dense urban environments. In (91) words, even if we were witnessing rapid population growth, that would not mean that the (92) were filling in with people. (93) , the urban areas would tend to become more crowded. Historically, we find that people have moved to (94) the jobs were. Jobs were usually in ports or locations with many natural (95) . After transportation became relatively cheap, other geographical locations became (96) of economic activity. One factor that determines where people will move to, even when transportation becomes cheap, is (97) . And individuals working in cities (98) higher incomes than those working in (99) areas. Hence, population has tended until the 1970s to (100) in our major urban centers. Recently population has (101) out of the Northeast to the South and to the West for the more pleasant climates. If people did not (102) from living in large cities, there would likely be a much more even population distribution (103) our entire land area. Probably, if this (104) the case, there would be less concern over population (105) Indeed, one need only (106) a cross-country drive or plane trip to realize how (107) populated these United States really are. This is not to say that we should or should not do something about (108) growth. The shortage of people in certain areas merely demonstrates that overpopulation in the United States is really only a problem in (109) urban environments. And this problem may be slowly correcting (110) .

A．take

B．start

C．engage

D．arrange
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