探放水过程中，掘进距水作业地点0.5m时，应改用手镐落煤
正确
暂无解析
Weregretto________thatitmaynotbepossibletodealwitheveryrequest.
Heaskedmewhethermybrother________(fly)toBeijing.
曲线的渐近线条数()
设f(0)=0,则f(x)在x=0处可导の充要条件为（）
Thistest________anumberofmultiplechoicequestions.