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: An eye can be of many different colours.

SOLUTION: An alphabet can be of many opposing colours .

PROBLEM: When everyone in the world is slaughtered , it 's a world war .

SOLUTION: When everyone in the world is fighting, it's a world war.

PROBLEM: You are likely to find a drop in a town .

SOLUTION:
You are likely to find a library in a town.