Annealing
Annealing is a way of making metal softer by heating it and then letting it cool very slowly, if metal is heated and then cooled very quickly, for example by dipping(浸) it in water, it will be very hard but also very brittle(脆)—that is, it will break easily. Metal that has been annealed is soft but does not breaks as easily. It is possible to make metal as hard or as soft as is wished, by annealing it. The metal is heated, and allowed to cool slowly for a certain length of time. The longer the heated metal takes to cool slowly, the softer it bees. Annealing can also be used on other material, such as glass.
1. Annealing can make metal
A. hard and tough(韧) B. hard but brittle C. soft but tough D. soft and brittle
2. Why do people put hot metal in water?
A. To make it hard. B. To make it soft. C. To make it cool. D. To make it brittle
3. In annealing, the required hardness of a metal depends on
A. the quantity of water used B. the temperature of the metal
C. the softness of the metal D. the timing of the operation
4. As suggested by the text, how can glass be made less brittle?
A. It can be heated and then cooled quickly.
B. It can be cooled and then heated slowly.
C. It can be heated and then cooled slowly.
D. It can be cooled and then heated quickly.1---4 CADC
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(答案→)1---4 CADC
解析：1.此题属词句意义理解题。文章第一句“Annealing is a way of making metal sofer”。第三句“Metal that has been annealed is soft but does not break as easily”．其中“does not break as easily”的意思就是“tough”．因此C项符合要求。A和D两面中均有一方面与上文不符。B中两方面均不符。因此都被排除。C为正确答案。
2.本题属推断归纳题。文中第一句：”if metal is heated and then cooled very quickly, for example by dipping it in water, it will be very hard but also very brittle”.意思是说如果把金属加热，然后迅速放到水里冷却，也就会变得非常硬，但也变得脆。“bald”是工艺的主观目的。“brittle”是伴随的客观结果。因此选A而不选D,B项与题目不符:C项是手段不是目的。因此，都可被排除。A为正确答案。
3.此题属概括归纳题。timing是时间的选择。本答案的依据是5和6两句，“The metal is heated，… length of time．”“The longer…the softer it bees．”，“。cool”的时间是可以控制的，时间越长就越“soft”，即硬度就越低。由此我们可得出结论：在退火过程中，金属的硬度是受到冷却的时间长短影响的。文章中没有提到退火时使用的水的数量，没有提到金属的温度，也没有提及金属的软度。因此这三答案均被排除。D为正确答案。
4.此题属推理判断题。文中最后一句说“Annealing can also be used on other materials ,such as glass.”很明显退火这工艺同样可用于象玻璃一类的其他材料。文中我们已知“annealing”就是先“heat”后“。cool slowly”．由此推断C是正确的。A项中“Cooled quickly”不符合上述工艺要求。B和C工艺程序都不对。因此，A、B、D三项被排除。C为正确答案.