题干

在如图所示的电路中,闭合开关S,电路正常工作.一段时间后灯熄灭,一个电表的示数变大,另一个电表的示数变小.将R和L位置互换后再次闭合开关S,两个电表指针不动.若电路中只有一处故障,则这个故障是____(选填“R”或“L”)发生____(选填“短路”或“断路”).

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L,断路

同类题1

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                                                                                Get a Thorough Understanding of Oneself.

    In all one's life lime it is oneself, that one spends the most time being with or dealing with.____.

    When you are going upwards in life you tend to overestimate yourself. It seems that everything you seek for is within your reach,____ It's likely that you think it wise for yourself to stay away from the outer world. Actually, to get a thorough understanding of oneself, you may as well keep the following tips in mind.

Gain a correct view of oneself.

    You may look forward hopefully to the future but be sure not to expect too much, for dreams can never be fully realized. You may be courageous to meet challenges but it should be clear to you where to direct your efforts.____

Self-appreciate.

    Whether you compare yourself to a towering tree or a blade of grass, a high mountain or a small stone, you represent a state of nature.____ If you earnestly admire yourself you'll have a real sense of self-appreciation.

____ In time of anger, do yourself a favor by releasing it in a quiet place so that you won't be hurt by its flames; in time of sadness, do yourself a favor by sharing it with your friends so as to change a bad mood into a cheerful one; in time of tiredness, do yourself a favor by getting a good sleep.

Get a full control of one's life.

    Then one will find one's life full of color and favor.

A. It has its own value.

B. Do oneself a favor when it's needed.

C. Do yourself a favor when you resist the attack of illness.

D. But it is precisely oneself that one has the least understanding of.

E. Especially if it is well within your reach, you are just too blind to see it.

F. When you are going downhill you tend to underestimate yourself for your own incompetence,

G. o long as you have a perfect knowledge of yourself, there won't be difficulties you can't overcome.

同类题4

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隐形杀手——甲醛

    ①甲醛是一种无色、有强烈刺激性气味的气体。广泛存在于生活之中,尤其是室内装修材料中的甲醛,危害极大。人们往往谈“醛”色变,这是为什么呢?

    ②装修污染问题,早在20年前就已经出现,虽然近年来公众的防治意识不断增强,但由于材料污染仍然存在,且范围极广,污染无法得到根本性解决。家庭中最常见的甲醛污染源,就是板材,尤其是人造板所含的脲醛胶。市场上几乎90%的复合地板、密度板等建材,都使用了脲醛胶。人们在装修房屋时,都无法避免。

    ③如果空间相对密闭,甲醛的挥发时间会非常漫长。早在十几年前,有关专家就研究指出,人造板等装修材料中含有的甲醛,释放时间在3—15年左右,那是一个何等漫长的挥发时间啊。

    ④甲醛浓度过高,会引起人体不适。当空气中甲醛浓度超过___1___毫克/立方米时,人会感到眼睛受刺激、咽喉疼痛;如果在甲醛浓度超过___2___PPM的空气中停留几分钟,人会泪流不止。如果长期接触低浓度甲醛,可能引起慢性呼吸道疾病,新生儿染色体异常,甚至致癌,可见甲醛对人类的健康危害是极大的。1995年,甲醛被国际癌症研究机构确定为可疑致癌物,而到了2004年,世界卫生组织就已经在公告中明确将甲醛上升为一级致癌物。

    ⑤面对人们身边的隐形杀手——甲醛,国家应该制定新标准,把含有脲醛胶的建材,从百姓家中清除出去,用无甲醛添加的新材料替代,最终才能从源头上消除其危害。