A.礫石B.粘土C.粗砂D.灰?guī)r
A.積水線B.探水線C.警戒線D.放水線
A.水文地質(zhì)條件簡(jiǎn)單的礦井B.水文地質(zhì)條件一般的礦井C.水文地質(zhì)條件中等的礦井D.水文地質(zhì)條件復(fù)雜的礦井