给出一句简单的英文句子，使用同义词或短语替换其中的一个词，并解释两个词或短语之间的关系。 
The cat sat on the mat.
The feline perched on the rug. 

"Cat" is a synonym of "feline". Both words refer to the same kind of animal. "Mat" can be replaced by "rug", which is a similar object used for covering floors.