Arccos
反余弦
🗣️ 情景例句
A dollar is valued at eight point two RMB yuan.
一美元价值8.2元人民币。
Dad is building another room onto the back the house.
爸爸另外在屋子的后面盖一个房间。
If you learn even a little English, you will find it usedful after you leave school.
假如你哪怕只是学一点英语，毕业后，也会发现它是有用的。