If you can't, wear gauzemask or anything that can cover your mouth and enable you to breath.
如果不行，戴上薄纱口罩或任何可以盖住嘴巴又能保证呼吸的东西。
2
Roll up a gauzemask to a long strip, then squeeze in mouth and tighten the rope on ears.
把口罩叠成一个长条，勒在嘴巴里后再把绳子套在耳朵上。
3
Good ventilation is required in the casting shop and sanding shop. Operators must wear gauzemask at work to prevent harm of metal powder to human body.