Ppm.
[医] 兆比率(百万分之几)
🗣️ 情景例句
If your pet turtle gets sick, take him to the vet.
如果你的宠物龟病了，带它去看兽医。
Karl was so upset that he began to turn red with anger.
卡尔非常惊讶，红着脸开始生气了。
Yes, it is.
是的，是我的。