Blc
abbr. 附面层控制（boundary layer control）
🗣️ 情景例句
Did you go home?
你回家了吗？
How long will you be away?
你将离开多久？
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。