Ppbv
abbr. parts per billion by volume 十亿分体积比
🗣️ 情景例句
Is this all Grandpa's stuff?
这里面都是爷爷的东西吗？
Can I take a message?
要我传话吗？
Arthur C.Clark once suggested a revolutionary idea passes through three phases:
Arthur C.Clark曾经提出，一个革命性的想法经过三个阶段：