Pericycloid
週摆线
🗣️ 情景例句
It's time we hired a secretary to answer the phones.
我们早就该请一个秘书接听电话了。
Those who climb high often have a fall.
爬得高往往跌得重。
The beautiful are envied by the ugly.
美人总为丑陋者所嫉妒。