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问题 填空题

如图1、图2所示，日食、月食、影子都是由于______形成的．

答案

当月球转到地球和太阳之间，月球挡住了太阳照向地球的光，我们就看不到太阳，这就是日食；

当地球、太阳、月亮在同一直线上，地球到了月球和太阳的中间，太阳光无法射到月亮上面．所以在地球上观测月球便有一块区域出现了阴影，这就是月食，是由于光的直线传播形成的；

影子是由于光照射到不透明的物体形成的阴影部分，是由于光的直线传播形成的．

故答案为：光的直线传播．

单项选择题

经皮穿刺椎间盘切除术后4天出现剧烈腰痛，同时出现发热，双下肢出现运动或感觉异常.最常见于那种情况？（）。

A.神经损伤

B.椎间盘感染

C.椎体滑脱

D.局部血肿

E.纤维环破裂
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单项选择题

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 (1) a job or advancing in one, the ability to read and comprehend (2) can mean the difference between success and failure. Yet the unfortunate fact is that most of us are (3) readers. Most of us develop poor reading (4) at an early age, and never get over them. The main deficiency (5) in the actual stuff of language itself—words. Taken individually, words have (6) meaning until they are strung together into phrases, sentences and paragraphs. (7) , however, the untrained reader does not read groups of words. He laboriously reads one word at a time, often regressing to (8) words or passages. Regression, the tendency to look back over (9) you have just read, is a common bad habit in reading. Another habit which (10) down the speed of reading is vocalization—sounding each word either orally or mentally as (11) reads.

To overcome these bad habits, some reading clinics use a device called an (12) , which moves a bar(or curtain) down the page at a predetermined speed. The bar is set at a slightly faster rate (13) the reader finds comfortable, in order to "stretch" him. The accelerator forces the reader to read fast, (14) word by word reading, regression and subvocalization practically impossible. At first (15) is sacrificed for speed. But when you learn to read ideas and concepts, you will not only read faster, (16) your comprehension will improve. Many people have found (17) reading skill drastically improved after some training. (18) Charlie Au, a business manager, for instance. His reading rate was a reasonably good 172 words a minute(19) the training; now it is an excellent 1,378 words a minute. He is delighted that how he can (20) a lot more reading material in a short period of time.

第（19）空应选择（）

A．for

B．in

C．after

D．before
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