Peruvite
硫银铋矿
🗣️ 情景例句
Mr. Douglas is currently on leave.
道格拉斯先生眼下正在休假。
He will speak about the sales projections for the coming year.
他将谈谈未来一年的销售计划。
below 20 per cent, its bactericidal action is negligible.
浓度低于20％时，杀菌能力基本上就不存在了。