常见顶板事故中，煤壁由支承压力作用，被压酥的过程叫（）
A.片帮
B.局部冒顶
C.大面积切顶
参考答案：A
Had they known what was coming next, they________ second thoughts. [ ]
A. may have
B. could have
C. must have had
D. might have had
硫酸分离罐液面过高是由于（）
A.硫酸循环量过多
B.氯气压力过大
C.纳氏泵硫酸入口阀开启过小
