金属在长期高温下金相组织结构发生的变化有以下()几种。
A、石墨化;
B、合金元素在固溶体和碳化物相间的重新分配;
C、结焦;
D、发生时效使组织中产生新相。
参考答案:A, B, D
-Which of these English CDs do you think I should buy, sir?
-__________ You're supposed to have ideas of your own.[ ]
A. It's up to you.
B. That's settled.
C. With pleasure.
D. I've got that.
船用大中型柴油机活塞头和活塞裙分别用()制造。
A.耐热合金钢和耐磨铸铁
B.耐热和耐磨合金钢
C.耐磨合金钢和耐热铸铁
D.耐热铸铁和耐磨铸铝