Underair
大氣最下層
??? 情景例句
Yes.
是的。
Don't forget to put stamps on the letter before you mail it.
不要忘記在寄信以前把郵票貼在信封上。
it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested.
提出把它作為星際間唯一可辨認的廣播頻率就為期不遠了。