Arccos
反余弦
🗣️ 情景例句
Please forgive me, Susan, but...
请原谅我 ，Susan， 但……
My parents speak English perfectly.
我的父母能流利地说英语。
Thirteen is not as good as one, but it's better than nothing.
“13下是不如1下好，但总比1下也不敲强。