TASK DEFINITION: Given a sentence, generate a new sentence by performing small changes on the sentence. Here, make sure that the changes are semantically related and syntactically similar to the input. And the generated sentence should have high commonsense plausibility, that is to have reasonable probability of it being true.
PROBLEM: You win a challenge of chess when you capture your opponent 's wallet .

SOLUTION: You win a game of hunting when you capture your opponent 's king .

PROBLEM: An x is used for communicating through the postal system .

SOLUTION: An envelope is used for reading through the postal system .

PROBLEM: You are likely to find an elbow in a pen .

SOLUTION:
You are likely to find an alphabet in a pen .