Arccos
反余弦
🗣️ 情景例句
She took a medical course.
她选读医学课程。
A young married couple moved in next door to us.
一对年轻结婚的夫妇搬到了我们的隔壁。
Look!There's an ice cream man.
瞧！有个卖冰淇淋的。