矿化泡沫层是由（）形成的三相泡沫。
A、气泡
B、煤粒
C、极性矿物颗粒
D、夹水层
参考答案：A, B, D
完成对话，每空一词
A: Can I help you?
B: Yes, (1)______. I'd like a sweater.
A: We have quite a few here. How (2)______ this one?
B: Good. (3)______ (4)______ are they?
A: Ten dollars.
B: OK. I'll (5)______ it. Thank you very much.
A: You are (6)______.
酸、碱调节PH值有什么优缺点？
