Task: Story Composition
Input (English): Premise: Bob went to the doctor for a routine visit. 
 Initial Context: The doctor said Bob was deficient in vitamin B12. 
 Original Ending: The doctor recommended a vitamin supplement. Bob went to the vitamin store and bought B12 supplements. The next time Bob went to the doctor, his B12 levels were perfect! 
 Counterfactual Context: The doctor said Bob was deficient in iron.
Output (English): The doctor recommended a vitamin supplement. Bob went to the vitamin store and bought iron supplements. The next time Bob went to the doctor, his iron levels were perfect!