采掘工作面风流中瓦斯浓度达到（）%时，必须停止用电钻打眼。
A.0.1
B.0.5
C.1
D.2
参考答案：C
---Have you ______ some new ideas?
--- Yeah, I’ll tell you later.
A．come about
B．come into
C．come up with
D．come out with
新建加热炉烘炉时温度控制分哪几个阶段？
