Rarefication
n. 变稀薄, 稀薄
🗣️ 情景例句
Where are you going during Summer vacation?
暑假你打算去哪儿？
He has forgotten about his job.
他把工作忘得一干二净。
it must be known to any kind of radio astronomer in the universe.
这个频率是宇宙中任何射电天文学家都应该熟悉的。