Preconcentration
n. 预选；预浓缩；预先富集
🗣️ 情景例句
Fifteen minutes! Thank you. Good-bye.
十五分钟 ！谢谢 。再见。
Wisdom is better than gold or silver.
智慧胜过金银。
Did you enter the contest?
你参加比赛了吗？