Ppbv
abbr. parts per billion by volume 十亿分体积比
🗣️ 情景例句
I have tea with y colleagues in the afternoon.
下午我和同事喝茶。
Pleasant hours fly fast.
欢乐的时间过得快。
The porter, however, could not understand me.
然而搬运工却不明白我的话。