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 run a mother in a pack .

SOLUTION: You are likely to find a mother in a pharmacy .

PROBLEM: You are likely to find a grape in a lunch box.

SOLUTION: You are likely to find a number in a result box .

PROBLEM: You can use a pillow case to cover and protect your skull .

SOLUTION:
You can use a pillow case to cover and protect your stuff .