Task: Story Composition
Input (English): Premise: Mark said if Nancy mowed the lawn he would buy her a root beer float. 
 Initial Context: Nancy mowed the lawn. 
 Original Ending: When she finished Mark went to go get her a root beer float. When Mark returned he only had a empty cup. Mark said he got thirsty and drank the root beer float. 
 New ending: Thinking that she finished, Mark went to go get her a root beer float. When Mark returned he only had a empty cup. Mark said he got thirsty and drank the root beer float. 
Output (English): Nancy did not mow the lawn though.