Why is Lee's cat catching the mice?和Why isn't Lee's cat catching the mice?有啥区别?怎么理解这两句,我只学过is lee's这种情况,即没加否定的

Why is Lee's cat catching the mice?和Why isn't Lee's cat catching the mice?有啥区别?怎么理解这两句,我只学过is lee's这种情况,即没加否定的 -----------------------------?That cat is Lucy's. -----------------------------?That cat is Lucy's. cat`s why does your cat blue 还是 why does your cat is blue cat Cat cat Is the tiger the cat's teacher? This is Beth's cat划线提问 ------- [ ]is the cat?-----It's only one. (3)Where is the cat?lt's 什么 is your mother's cat? What color is your cat 's BE动词和助动词在这句话中的用法疑问.课本上的语句是：why isn't Mrs.lee's cat catching the mice?可catching应该是动词,理论语句应该用助动词don't/dosen't如下：why dose't Mrs.lee's cat catching the mice?到底哪 Lucy's hat l_____ like a cat.怎么添?Why? 填空( )cat is fat.填the or an?why 填空 it is the girl's cat.itis.填空 it is the girl's cat.itis.