根据脱氧程度所表示的状态，分为（）三类。
A.镇定钢
B.半镇定钢
C.沸腾钢
D.半沸腾钢
参考答案：A, B, C
根据句意，用括号内所给单词的正确形式填空。
1. 一I _________ (have) lunch when Bill knocked at the door.
2. He used to enjoy _________ (listen) to rock music.
3. Chinese tigers live in the south of China. They aye the _________ (old) typle of tigers living in the world.
4. The rainforests can give us a lot of _________ (use) things.
5.一Would you mind _________ (teach) me? 一Not at all.
化学课程目标的陈述结构中最基本的成分是______
A．主体 B．行为 C．条件 D．程度
