Evolvent
渐开线, 切展线
🗣️ 情景例句
Well, Grandpa, you're about five-nine or five-ten.
嗯， 爷爷。你大概是五英尺九或者五英尺十。
Turn up your radio please.
请你把收音机开响一点儿。
He sat in the darkness and listened to the people around him.
他坐在黑暗处，听着周围的人在讲话。