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问题 选择题

在室温下，将下列物质各5g分别放入50g水中搅拌后观察，现象最相似的是（）　　　　

A．Fe2(SO4)3、KMnO4

B．CuSO4、NaCl

C．CuO 、MnO2

D．NaOH、NH4NO3

答案

答案：C

分析：根据物质溶解时的现象分析，从物质的溶解性，所得溶液的颜色，溶解时的吸热或放热现象判断．

解：A、Fe2（SO4）3溶于水所得溶液为黄色，KMnO4溶于水溶液为紫红色，现象不同，故A错误；

B、硫酸铜的水溶液为蓝色，而氯化钠的水溶液为无色，现象不同，故B错误；

C、CuO、MnO2都是不溶于水的黑色固体，现象相同，故C正确；

D、氢氧化钠溶于水放出大量的热，而硝酸铵溶于水吸热，现象不同，故D错误；

故选C．

点评：本题考查了常见物质的溶解性，完成此题，可以依据已有的知识进行，要求同学们在平时的学习中加强基础知识的储备，以便灵活应用．

问答题 简答题

试列出如图所示系统实现“快进—I工进—II工进—快退—停止”工作循环的电磁铁动作顺序表（电磁铁通电记“+”号，断电记“—”号）。
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单项选择题

The nobler and more perfect a thing is, the later and slower it is becoming mature. A man reaches the mature (1) of his reasoning powers and mental faculties (2) before the age of twenty-eight; a woman at eighteen. And then, too, in the case of woman, it is the only reason of a sort--very mean in its (3) . That is why women remain children their whole life long; never seeing (4) but what is quite close to them, (5) fast to the present moment, taking appearance for (6) , and preferring (7) to matters of the first importance. For it is (8) his reasoning faculty that man does not live in the present only, (9) the brute, but looks about him and considers the past and the future; and this is the origin of (10) , as well as that of care and anxiety which so many people (11) Both the advantages and the disadvantages, which this (12) , are (13) in by the woman to a smaller extent because of her weaker power of reasoning. She may, in fact, be described as intellectually shortsighted, (14) , while she has an immediate understanding of what lies quite close to her, her field of (15) is narrow and does not reach to what is (16) ; so that things which are absent, or past, or to come, have much less effect upon women than upon men. This is the reason why women are inclined to be (17) and sometimes carry their desire to a (18) that borders upon madness. In their hearts, women think it is men’s business to earn money and theirs to spend it--if possible during their husband’s life, (19) , at any rate, after his death. The very fact that their husband hands them (20) his earnings for purposes of housekeeping strengthens them in this belief.

5（）

A.fastening

B.sticking

C.taking

D.seeing
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