专用排瓦斯巷道回风流中的瓦斯浓度不得超过（）巷道内风速不得低于（）。
参考答案：2.5%，0.5m/s
So that even the students in the next classroom could hear his argument with somebody.
A．loudly he spoke
B．he spoke loudly
C．loudly did he speak
D．loudly spoke did he
哪些机构共同构成了银行卡产业链（）
A.发卡机构
B.收单机构
C.转接清算机构
D.第三方服务机构
