Preconcentration
n. 预选；预浓缩；预先富集
🗣️ 情景例句
Nothing much. I'm just taking one day at a time.
没什么。我只是过一天是一天。
I'd like to make an appointment to see Mr. Cooper.
我想预约见库珀先生。
A burst of activity associated with the laying of submarine cables soon confirmed the Challenger's observation that many parts of the ocean were two to three miles deep,
海洋中很多地方可深达两三英里，