troughs

例句:

• There have been peaks and troughs in the long-term trend of unemployment.
  长期以来失业率一直时起时伏。
  
• Before such combination, they were troughs and crests.
  来自SA
• Pigs lined the troughs, jostling, squealing, eating their swill.
  来自I. Wallace
• The boat rolled heavily in the troughs between the waves.
  船在波涛起伏的海浪中剧烈摇摆。
  
• The business cycle is a series of peaks and troughs.
  商业周期是一系列的高峰期和低谷期.
  
• Instead, peaks and troughs are navigated by the song's lyrics.
  来自BBC