Peritrochoid
外摆线圆
🗣️ 情景例句
The costs of college get higher every year.
学费逐年增加，越来越贵。
When did you get off work?
你什么时候下班？
There's no time! laughed Mother.Here are the twins.
“没时间了！”母亲笑着说，“双胞姐妹到了。”