安装工作在井底坑内进行的是对重装置和()。
A.缓冲器
B.限速装置
C.安全钳
D.曳引机
参考答案:A
解析:
安装工作在井底坑内进行的是对重装置和缓冲器。
— How many people learn English as a second language?
— ________, there are more than 375 million people. [ ]
A. What's more
B. In total
C. At all
D. First of all
烟囱排放烟气粉尘含量:推焦除尘()mg/m3;装煤除尘()mg/m3