有些小同学有事没事的时候，喜欢用手指头挖鼻孔。同学们可知道，我们的鼻孔里长满了许多黑色的鼻毛，它可以像卫士一样阻挡灰尘和杂物的侵入。鼻孔里还有一层非常娇嫩（jiāonèn）的粘膜（niánmó），上面分布着许多血管。这些血管很脆弱（cuìruò），经常挖鼻孔，就会很容 Some students do not matter when something small, like to dig your nose with your fingers. Students will know that our nostrils are full of many black nose hair, which can stop the invasion of dust and debris like a guard. There is a very nostril on the nostrils that contains many blood vessels. These blood vessels are very fragile, often digging nostrils, will be very tolerant