给你一个句子，要求你将其中的谓语动词提取出来，并将其变成进行时态。并返回修改后的句子。
The cat is lying on the sofa.
原句：The cat is lying on the sofa.

提取谓语动词：lying

改为进行时态：is lying → is/are/am + verb + -ing → is lying → is/are/am lying

修改后的句子：The cat is lying on the sofa. → The cat is/are/am lying on the sofa.