Preconcentration
n. 预选；预浓缩；预先富集
🗣️ 情景例句
I think I've got them all, but I'm not sure.
我想我都已经拍齐了， 但我不能肯定。
I would like to call an eletrician to come this afternoon.
我要叫一个电器师傅今天下午来。
Just now we all watched you sign to show that you had received the cheque.
刚才我们大家都观察到了你为表明已收到那张支票而签名。