石油焦在煅烧时固定碳损失有三种途径分别是什么?
参考答案:
1、固定碳在炉床上燃烧损失。
2、烟气携带炭粉的燃烧损失。
3、烟气携带走的炭粉损失。
危急遮断油门的作用是什么?如何操作?
— Do you have any idea why the bus-drivers are on strike?
— As far as I know, they are _____ a pay rise. [ ]
A. calling off
B. calling at
C. calling in
D. calling for