参考答案（飞行员应答）
The main differences between PBE and an oxygen mask are their purpose, design, and usage environment. An oxygen mask is used primarily for high altitude operations — when cabin pressure is lost, the mask delivers pure oxygen to prevent hypoxia. It does not protect against smoke or toxic fumes. A PBE, on the other hand, is designed for smoke, fire, or chemical fume emergencies. It covers the entire head, including eyes and face, and provides filtered air or chemical oxygen. Another difference is duration: oxygen masks are connected to the aircraft’s oxygen system, which can last much longer, while PBE has a limited 15 to 20 minute supply. Finally, oxygen masks are stored above each seat, while PBE is stored in a container in the cockpit. Pilots must know how to use both — they serve different emergencies.
PBE
和氧气面罩的主要区别在于用途、设计和使用环境。氧气面罩主要用于高空运行 —— 当客舱失压时，面罩提供纯氧以防止缺氧。它不能防护烟雾或有毒烟雾。而 PBE 是为烟雾、火灾或化学烟雾紧急情况设计的。它覆盖整个头部，包括眼睛和面部，并提供过滤空气或化学氧气。另一个区别是持续时间：氧气面罩连接到飞机的氧气系统，可以使用更长时间，而 PBE 只有有限的 15 至 20 分钟供应。最后，氧气面罩存放在每个座位上方，而 PBE 存放在驾驶舱的容器内。飞行员必须知道如何使用两者 —— 它们应对不同的紧急情况。