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问题 单项选择题

下列属于回火目的的是( )。

A．得到马氏体或贝氏体
B．稳定工件尺寸
C．提高钢的强度和耐磨度
D．改善钢的塑性和韧性

答案

参考答案：B

问答题 简答题

常用的工业催化剂的制备方法有哪些？各自的有缺点及适用场合是什么？
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填空题

CONVERSATION 2 (Questions 5-8)


Jeff has lived in New York for (5) years.
Jeff doesn’t like (6) , (7) and (8) of New York.

CONVERSATION 2(Questions 5-8)


The woman is working at the campus (5) office.
The man can work at least (6) hours a week but not more than (7) hours a week from (8) on.
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