Yo-Yo
n
(pl ~s) (propr 專利名) 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, 為木制或塑料制兩厚圓盤, 中間有一深溝連接一繩, 用手指抻繩可使之沿繩上下移動)
The price of petrol is going up and down like a Yo-Yo. 汽油的價格像悠悠一樣忽上忽下.