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: 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: The effect of walking around a pavement is getting sore muscles .

SOLUTION: The effect of walking around a course is getting sore muscles .

PROBLEM: Old books may be of greater value than single books .

SOLUTION:
Old books may be of greater value than outdated books .