Ppb
[化] 十亿分率
🗣️ 情景例句
I need a CD-ROM recorder.
我想要一个光盘刻录机。
To really understand a man we must judge him in misfortune.
要真正了解一个人，需在不幸中考察他。
So how can I help you ? asked the detective.
那么我怎样才能帮你呢？侦探问。