closed circuit breathing apparatus

例句：

1. 1. The medical teamused a closed-circuit respirator to treat the patient's respiratory condition.
   医疗团队使用封闭式呼吸器来治疗病人的呼吸状况。
2. 2. The engineer designed a closed-circuit breathing apparatus for the construction site.
   工程师为工地设计了一款封闭式呼吸设备。
3. 3. During emergencies, the firefighters rely on their closed-circuit breathing apparatus to stay safe.
   在紧急情况下，消防员依靠他们的封闭式呼吸设备来保持安全。