impurities of wool

例句：

1. 1.The wool was so dirty that it needed to be washed before we could wear it.
   羊毛非常脏，需要洗才能穿。
2. 2.The manufacturer has identified several impurities in the product.
   制造商已经确定了产品中的几个杂质。
3. 3. The impurities in the water were causing the pipes to clog.
   水中的杂质导致管道堵塞。