男孩子到了十六七岁,随着性发育的逐渐成熟,口唇部开始出现胡须,这是一种很自然的现象。但是有些男孩子认为长胡须不好看,爱用手或镊子一根一根地拔,这是一种不良的卫生习惯。胡须是毛发的一种,在结构上同身体其他部位的毛发一样分为三部分:露出皮肤外面的部分叫毛干,埋在皮肤 When the boy reaches the age of sixteen or seventeen, as the sexual development gradually matures, the beard begins to appear on the lips. This is a very natural phenomenon. But some boys think long beard does not look good, love to use hand or tweezers one by one pull, this is a bad health habits. Beard is a kind of hair, structurally the same as the rest of the body hair is divided into three parts: the exposed part of the skin called the hair shaft, buried in the skin