第二类回火脆性
参考答案：
对含有锰、铬、镍等元素的合金调质钢，淬火后在450—650；℃回火，保温后缓冷时钢的韧性下降的现象。
阅读理解，将正确答案的序号填入题前括号里。
This is my pen pal. His name is Tang Wei. He works in the hospital. He helps sick people. He likes making
kites. He goes to work by subway.
1. Where does Tang Wei work? He works in the _____________.
A. hospital
B. school
C. cinema
2. He likes _____________.
A. making kites
B. swimming
C. singing
3. How does he go to work? He goes to work _____________.
A. by taxi
B. by subway
C. by bike
缓解急性心肌梗死剧烈疼痛效果最好的是（）
A.硝酸甘油
B.二硝酸异山梨醇
C.罂粟碱
D.吗啡
E.可待因
