The checkups were a good idea, but she needn't have panicked.检查是个不错的主意, 但大可不必惊慌.You needn’t feel any guilt about me.你用不着因为我而內疚。You needn't worry...你不必担心。"I'll put the key in the window." — "You needn'...
分析了闪速冶炼中石英砂品质对冰铜生产的影响,以探求取得更好经济效益的途径.The influence of quartz sand quality on mattes production in flash smelting is analyzed.研究了高品位铜冰铜转炉吹炼石英熔剂熔化行为.Melting behavior of silica flux in the converting process of high grade c...