Ppm.
[医] 兆比率(百万分之几)
🗣️ 情景例句
but I prefer a two-story home.
但我喜欢两层楼的房子。
The doctor advised me to drink plenty of water.
医生劝我要多喝水。
She is standing in the front of the bus.
她站在公共汽车的前部。