下列（）应设置辅助隔爆棚。
A、采煤工作面进回风巷
B、相邻煤层运输石门
C、采区间集中运输大巷
D、主要运输大巷
参考答案：A
___ countless failures, the scientist finally succeeded in discovering the chemical substance. [ ]
A. Suffered
B. Being suffered
C. To suffer
D. Having suffered
何谓脱火？
