Peritrochoid
外摆线圆
🗣️ 情景例句
The policemen could not cope with the crowds.
警察不能对付群众。
He who rides a tiger is afraid to dismount.
骑虎者难下。
there is no evidence that the total amount of activity is any less.
但没有迹象表明，其活动总量有任何减少。