Task: Story Composition
Input (English): Premise: Tim went sledding with friends one day. 
 Initial Context: He took his favorite sled. 
 Original Ending: He started down the hill fast. He couldn't move out of the way when headed for a boulder. Tim crashed and destroyed his sled. 
 Counterfactual Context: He couldn't find his favorite sled.
Output (English): Tim had to pick an old one, he started down the hill fast. He couldn't move out of the way when headed for a boulder. Tim crashed and destroyed his old sled.