Ppm.
[医] 兆比率(百万分之几)
🗣️ 情景例句
I'm just calling to confirm your appointment tomorrow at 3:00 p.m.
我打电话确认明天下午3点你约定的时间。
It's not up to his usual standard.
这次没有达到他平时的水平。
When a marked bee returned to the hive from the feeding table, Von Frisch watched through the glass.
当一只有记号的蜜蜂从喂食桌回到蜂箱时。