第二性征

例句：

1. 1. The boy's second-hand clothes are very popular among his friends.
   这个男孩的二手衣服在朋友中非常受欢迎。
2. 2. The female body has several secondary sex characteristics that distinguish it from the male body.
   女性身体有几个第二性特征，这些特征将女性与男性区分开来。
3. 3. The study of human evolution is often focused on identifying and understanding the secondary sex characteristics.
   人类进化的研究通常集中在识别和理解第二性特征上。