N-COUNT 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. 溜溜球，悠悠球（圆形玩具，抖动细绳时能上下移动）