急性肾盂肾炎，尿中可见 A.红细胞管型 B.白细胞管型 C.上皮细胞管型 D.透明管

人体对电流的反应

随着科技的飞速发展，各种电器设备的数量急剧增加，但同时也带来了更多的触电事故，因此，安全用电被人们所重视．人们往往认为：触电危害的原因是接触了高压，而触电危害的真正原因是有较大的电流通过人体．人体受到电击时，电流对人体的伤害程度主要与流过人体电流的大小有关，当手触及50Hz交变电流时，人体的反应如下表所示：

电流（mA）	人体反应
0.6-1.5	手轻微颤抖
2-3	手指强烈颤抖
5-7	手部肌肉痉挛
8-10	手难摆脱带电体，但还能摆脱，手指尖到手腕剧痛
20-25	手迅速麻痹，不能自动摆脱电源，手剧痛，呼吸困难
50-80	呼吸麻痹，心房开始震颤
90-100	呼吸麻痹，延续3s就会造成心脏麻痹

除电流大小的原因外，触电的部位、电流经过人体的时间也会影响触电的伤害程度．如果电流长时间通过人体，人体电阻会下降，即使电流很小，也是比较危险的．

请回答：

（1）根据欧姆定律可知：对于同一个人，电压越______，电流就越______，电流经过人体造成的伤害就越大．通过阅读，在防止人身触电事故方面你还学到了什么？

（2）用今天你学到的知识解释一下：为什么我们认为低于36V的电压才是安全的？

在一个请求分页系统中，采用LRU页面置换算法时，假如一个作业的页面走向为：1，3，2，1，1，3，5，1，3，2，1，5，当分配给该作业的物理块数分别为3和4时，试计算在访问过程中所发生的缺页次数和缺页率。

单缸四冲程内燃机，曲轴每转（）圈，气缸完成一工作循环。

A．4

B．3

C．2

D．1

质量为0.2kg的小球从高处自由下落，则下落第三秒末重力做功的瞬间功率为_________W，第三秒内重力做功的平均功率为____________W。（g取10m/s²）

For many people today, reading is no longer relaxation. To keep up their work they must read letters, reports, trade publications, interoffice communications, not to mention newspapers and magazines: a never-ending flood of words.
In (36) a job or advancing in one, the ability to read and comprehend (37) can mean the difference between success and failure. Yet the unfortunate fact is that most of us are (38) readers.
Most of us develop poor reading (39) at an early age, and never get over them. The main deficiency (40) in the actual stuff of language itself—words. Taken individually, words have (41) meaning until they are strung together into phrases, sentences and para-graphs. (42) , however, the untrained reader does not read groups of words. He laboriously reads one word at a time, often regressing to (43) words or passages.
Regression, the tendency to look back over (44) you have just read, is a common bad habit in reading. Another habit which (45) down the speed of reading is vocalization—sounding each word either orally or mentally as (46) reads. To overcome these bad habits, some reading clinics use a device called an (47) , which moves a bar (or curtain) down the page at a predetermined speed. The bar is set at a slightly faster rate (48) the reader finds comfortable, in order to "stretch" him.
The accelerator forces the reader to read fast, (49) word-by-word reading, regression and sub vocalization, practically impossible. At first (50) is sacrificed for speed. But when you learn to read ideas and concepts, you will not only read faster, (51) your comprehension will improve.
Many people have found (52) reading skill drastically improved after some training. (53) Charlce Au, a business manager, for instance, his reading rate was a reasonably good 172 words a minute (54) the training, now it is an excellent 1,378 words a minute. He is delighted that how he can (55) a lot more reading material in a short period of time.

[A] applying [B] doing [C] offering [D] getting