搅拌清水混凝土时应采用强制式搅拌设备,每次搅拌时宜比普通混凝土延长()。
A.10~20s
B.20~30s
C.30~40s
D.40~50s
参考答案:B
单项选择。
— Could you come here, please?
— .[ ]
A. Certainly.
B. Yes, I loved.
C. No, I couldn't.
D. Yes, I couldn't.
进料C.O2气中S含量偏高,如何进行设备防腐?