Yo-Yo
n
(pl ~s) (propr 专利名) toy consisting of two thick discs of wood or plastic with a deep groove between, which can be made to rise and fall on an attached string when this is jerked with a finger 悠悠(玩具, 为木制或塑料制两厚圆盘, 中间有一深沟连接一绳, 用手指抻绳可使之沿绳上下移动)
The price of petrol is going up and down like a Yo-Yo. 汽油的价格像悠悠一样忽上忽下.