求问这一段中的“bathtub This solid can be seen as a bathtub ring
问题描述：
求问这一段中的“bathtub This solid can be seen as a bathtub ring
上文：When soap is added to hard water,these ions react with the soap to make a solid precipitate,which is then not able to dissolve dirt in water.
答
bathtub ring
浴缸上一圈的污垢.
This solid can be seen as a bathtub ring
这些固体成为我们能在浴缸在上看到的那一圈污垢.