What is the dog doing?
The dog is chasing after the fish.
Why is the dog pushing rocks?
Because he wants to help the fish leap up/jump up the waterfall.
What is the fish doing?
The fish is trying to leap up the waterfall. (But he can't.)
Why is the fish sad?
Because he can't leap up/jump up the waterfall. // The fish is sad because it can't leap up the waterfall.
What is happening?
The dragon is flying. / The dog is riding on the dragon's back.
What is happening?
The fish transforms into a dragon. / The fish is transforming into a dragon.
What is the dog doing?
The dog is pushing a heavy rock. (He is making a stair for the fish.)
What is the fish/carp doing?
The fish is leaping out of the water.