我需要买口罩以防万一吗?
If it's very cold, consider wearing a face mask or scarf to warm the air before it enters your lungs.如果非常冷,可以考虑戴口罩或者围巾以使空气温暖的进入肺。
When it's really cold, wear a face mask or a scarf over your mouth to warm the air you breathe and protect your face.很冷的时候,戴一个面罩或者围巾遮住嘴,可以给你呼吸的空气保点温,同时也可以保护你的脸。