* You need to think outside the box. The problem isn't about physically getting them across the river. It's about preventing the cat from eating the mouse.
Here's a solution:
1. Carry the cat across the river.
2. Leave the cat on the other side and bring the dog back.
3. Take the mouse across the river.
4. Bring the dog back to the original side.
5. Carry the cat back to the original side.
Now, you have successfully transported the cat, dog, and mouse across the river without the cat eating the mouse!