司钻法和反循环法压井（）。
A.都是一个原理
B.不是一个原理
C.是两个概念
参考答案：A
There is no point arguing about what _____ the accident. The point is what to do with the victims of it. [ ]
A. led to
B. caused to
C. accounted to
D. resulted from
明杆闸阀的工作原理是什么？
