名词
1. 溜溜球，悠悠球（圆形玩具，抖动细绳时能上下移动）
A yo-yo is a toy made of a round piece of wood or plastic attached to a piece of string. You play with the yo-yo by letting it rise and fall on the string.
1. a toy consisting of a spool that is reeled up and down on a string by motions of the hand