Ppm.
[医] 兆比率(百万分之几)
🗣️ 情景例句
Thank you.
谢谢。
After Flagstaff, we'll go to San Diego.
到佛拉格斯塔夫之后，我们去圣迭戈吧。
So the number of stars that we know exist is now estimated at about 300 million million million.
因此，我们所知道的现有恒星数目估计约有30亿×1000亿颗。