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 unknown to find a wheelchair around in a farmers field .

SOLUTION: You are pleased to find a limp around in a farmers field .

PROBLEM: The effect of helping someone is improving a situation.

SOLUTION: The habit of helping someone is improving a situation .

PROBLEM: A teaching knife is a useful item for boys to carry .

SOLUTION:
A pocket knife is a useful item for boys to carry.