防护帽

例句：

1. 1. He put on his protective helmet before starting the construction work.
   他开始施工工作前戴上了防护头盔。
2. 2. The workers were required to wear protective helmets when working with heavy machinery.
   工人在操作重型机械时必须佩戴防护头盔。
3. 3. The driver wore a protective helmet while driving at high speeds.
   司机在高速驾驶时戴着防护头盔。