helmets

例句:

• Helmets do, however, protect against skull fracture.
  来自SA
• It is compulsory for all motorcyclists to wear helmets.
  所有骑摩托车的人都必须戴头盔，这是强制性的。
  
• The shop at the corner of the street sells helmets.
  街道拐角那家商店出售安全帽.
  
• Protective helmets must be worn on site.
  在工地必须戴防护帽.
  
• Some clubs allow members to hire bikes and helmets.
  来自BBC
• Officers wearing helmets restored order, arresting two people.
  来自WSJ