Ppb
[化] 十亿分率
🗣️ 情景例句
May I see the mirror, please?
我可以照照镜子吗？
No sweet without some sweat.
不劳则无获。
And, as in a nightmare, there was nobody in sight to help me.
就像在恶梦里一样，见不到一个人可以帮助我。