Ppbv
abbr. parts per billion by volume 十亿分体积比
🗣️ 情景例句
I see your point you mean.
我懂你的意思。
How long will it take me to get there?
到那儿要多长时间？
but custom, we have a way of thinking, is behaviour at its most commonplace.
至于风俗呢，只是些司空见惯的行为而已。