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 are likely to find a building in the know .

SOLUTION: You are likely to find a building in the back .

PROBLEM: If you want to recognize a computer then you should appropriate an application program .

SOLUTION: If you want to use a computer then you should mail an application program .

PROBLEM: You are likely to find a chess queen in a games store.

SOLUTION:
You are likely to find a chess pointer in a games store .