smokescreen         
noun [ C ] uk/ˈsməʊk.skriːn/ us/ˈsmoʊk.skriːn/
 (用于掩盖真实意图的)烟幕
something that hides the truth about someone's intentions
  Instead of doing something about the problem, the city council is hiding behind a smokescreen of bureaucracy. 市议会躲在官僚作风的烟幕后,不采取措施解决问题。 
  (战斗中用于隐蔽军队的行动和位置的)烟幕
an artificial cloud of smoke that is used to hide the movements or positions of soldiers from the enemy