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问题 单项选择题

第21—24题基于以下题干：　　某一伸缩自适应型控制系统能够根据组成系统组件的型号、数量和顺序的不同来执行相应的不同的控制功能。这个控制系统只能是由a、b、c、d、e这五个组件中的几个按从左到右的顺序组合而成，而且组件组合成控制系统必须符合以下规律：　　（1）两个或两个以上的组件才能组成控制系统，组成系统的组件可以相同也可以不同；　　（2）组件a不能出现在控制系统的最左边；　　（3）如果系统中存在组件b，那么它出现次数就不止一次；　　（4）在控制系统中c既不能是最后一个组件也不能是倒数第二个组件；　　（5）只要组件a出现，组件b就一定出现；　　（6）e如果是最后一个组件，则组件b一定出现。

下列哪一个是可能的控制系统的组成情况？

A．abbd

B．becb

C．cbbe

D．dcae

E．edac

答案

参考答案：C

解析：解析：正确答案是C.abbd违反了题干条件（2）；becb违反了题干条件（4）；cbbe符合题干所有条件的要求；dcae违反了题干条件（6）；edac违反了题干条件（4）。所以，应该选C.

单项选择题

腕垂症见于

A．尺神经损伤
B．桡神经损伤
C．正中神经损伤
D．colles骨折
E．缺铁性贫血
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单项选择题

Of all the areas of learning the most important is the development of attitudes. Emotional reactions as well as logical thought processes affect the behavior of most people.
"The burnt child fears the fire" is one instance. Another is the rise of despots like Hitler. Both of these examples also point up the fact that attitudes stem from experience. In the one case the experience was direct and impressive, in the other case it was indirect and cumulative. The Nazis were formed largely by the speeches they heard and the books they read.
The classroom teachers in the elementary school are in a strategic position to influence attitudes. This is true partly because children acquire attitudes from those adults whose opinion they respect.
Another reason is that pupils often delve somewhat deeply into a subject in school that has only been touched upon at home or has possibly never occurred to them before. To a child who had previously acquired little knowledge of Mexico, his teacher’s method of handling such a unit would greatly affect his attitude towards Mexicans.
The media through which the teacher can develop wholesome attitudes are innumerable. Social attitudes (with special reference to races and nationalities) science matters of health and safety, the very atmosphere of the classroom--these are a few of the fertile fields for the induction of proper emotional reactions.
However, when children come to school with undesirable attitudes, it is unwise for the teacher to attempt to change their feelings by cheating or scolding them. She can achieve the proper effect by helping them obtain constructive experiences. Finally, a teacher must constantly evaluate her own attitudes, because her influence can be harmful if she has personal prejudices. This is especially true in respect to controversial issues and questions on which children should be encouraged to reach their own decisions as a result of objective analysis of all the facts.

The word "harmful" in the last paragraph most probably means ______.

A. bad-affecting
B. ill-effective
C. widespread
D. irritating
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