单词：keep_down 

动词

• 
  [1.v.keep_down] (同义词:[number( n. 数, 数字, 数量, 号码, 算术, 诗, 韵律 v. 遍号码, 共计..., 计入, 计算, 算入 )]  [keep_down(v.卧下, 镇压, 控制, 缩减, 保留 )]  )
• 
  注释列句：place a limit on the number of
• 上位词 -> [limit( n. 界限, 限度, 限制 vt. 限制, 限定 )]  [decrease( n. 减少, 减少之量 v. 减少 )]  [change( n. 改变, 变化, 转变, 找回的零钱, 找头, 辅币 vt. 改变, 变革, 改造, 兑换 )] 
• 
  [2.v.keep_down] (同义词:[repress( vt. <美>再压, 补充加压 vi. 压制 )]  [quash( v. 取消 )]  [keep_down(v.卧下, 镇压, 控制, 缩减, 保留 )]  [subdue( v. 征服 )]  [subjugate( vt. 使屈服, 征服, 使服从, 克制, 抑制 )]  [reduce( vt. 减少, 缩小, 简化, 还原 )]  )
• 
  注释列句：put down by force or intimidation; "The government quashes any attempt of an uprising"; "China keeps down her dissidents very efficiently"; "The rich landowners subjugated the peasants working the land"
• 上位词 -> [oppress( vt. 压迫, 压抑 )] 
• 
  [3.v.keep_down] (同义词:[keep_down(v.卧下, 镇压, 控制, 缩减, 保留 )]  )
• 
  注释列句：manage not to throw up
• 反义词 -> [vomit( n. 呕吐, 呕吐物, 催吐剂 vi. 呕吐, 大量喷出 vt. 吐出, 呕吐 )]