Fēijī shàng de yǎngqì miànzhào huì zìdòng diào xiàlái.
The oxygen masks on the airplane will drop automatically.
Tips
usage
面罩 refers to masks that cover the full face or a large portion of it — gas masks, welding shields, oxygen masks. For the surgical/medical masks worn over the mouth and nose, use 口罩 (kǒuzhào). 面具 (miànjù) is used for decorative or theatrical masks.
