P. p. d.
[医] 精制蛋白衍化物(结核菌素)
🗣️ 情景例句
I remember when I used to be a Girl Scout.
我记得我还是一名女童子军的时候。
Two ears to one tongue, therefore hear twice as much as you speak.
两只耳朵对一舌，故应多听而少说。
As Earth-dwellers, we always cherish the hope that we will be visited by little green men and that we will be able to communicate with them.
小绿人来拜访我们，而我们可以和他们交流。