In such a severe circumstance, it has become one of the focuses of operation corporations that how to avoid customer churn and carry out retainment.
在这种形势下，如何防止客户流失、实施客户保持工作，已成为运营商关注的焦点之一。
2
The main target coal seam of Xieqiao Mine is directly covered with the Quaternary bottom gravels, whose impermeability affects the reasonable retainment of waterproof pillar.