Task: Story Composition
Input (English): Premise: Mark had always wanted to have a pet. 
 Initial Context: He decides to buy a pet cat. 
 Original Ending: Mark loves his new cat. He feels less lonely now that he has a cat. He is glad that he got a pet. 
 Counterfactual Context: He decides to buy a few fish.
Output (English): Mark loves his new fish. He feels less lonely now that he has a fish. He is glad that he got a pet.