Upperbound
上界
🗣️ 情景例句
I can't figure him out-he's a mystery!
我不能理解他，他真是个迷。
If it is left too long, it begins to give off a bad smell.
假如把它放得太久了，它就会开始发臭。
I will keep you posted.
我会与你保持联络。