规程规定煤层中夹矸的单层厚度不大于()时,夹矸与煤可合并计算,不需扣除。 ["0.01","0.05","0.1","0.2"]
下面不属于叶片式泵的有() ["离心泵","齿轮泵","螺杆泵","混流泵"]
当需要()时要提前做好各项准备工作。 ["A、提前预展","B、提前预铺","C、提前预挂","D、提前预吊"]
螺杆泵适用于输送下面的液体()。 ["润滑油","胶液","燃油","泥沙"]
当采用气举反循环排渣时,风管的下设深度一般不超过()m。 ["30;","40;","50;","60。"]
简述OSI模型。