Ppbv
abbr. parts per billion by volume 十亿分体积比
🗣️ 情景例句
How many people are there in your family?
您家有几口人？
Hiking gives you time to think.
郊游可以使你有时间思考。
This was later confirmed by naval official at the Ministry of Defiance after the Elkor had returned home.
这一说法在“埃尔科”号返航后得到的国防部一位海军官员的证实。