The old grey cat is sleeping, sleeping, sleeping
The old grey cat is sleeping in the house.
The little mice are creeping, creeping, creeping
The little mice are creeping in the house.
The old grey cat is stalking, stalking, stalking
The old grey cat is stalking in the house.
The little mice are scampering, scampering, scampering
The little mice are scampering in the house.
Here's another version you can try. Little children can pretend to be cats and mice and copy the actions in the song. If you have a big group of older children, half can pretend to be the cats and the other half can be the mice!
The old gray cats are sleeping, sleeping, sleeping
The old gray cats are sleeping in the house.
The little mice are creeping, creeping, creeping
The little mice are creeping in the house.
The little mice are nibbling, nibbling, nibbling
The little mice are nibbling in the house.
The old gray cats are creeping, creeping, creeping
The old gray cats creeping in the house.
The little mice are hiding, hiding, hiding
The little mice are hiding in the house.