1. The flight attendants display how to use air masks and floatation devices in the event of a plane crash.
2. In the airline industry, there is a provision that requires oxygen masks to be available for everyone on a flight in case of an emergency.
3. The men who work in the rock quarry wear masks to keep the stone particles out of their eyes.
4. After the bombing, people had to wear masks to avoid inhaling the malignant fumes of the chemical agents.
5. Masquerade masks allowed the poseur to go undetected at the king’s ball.