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: A pencil is discarded for writing .

SOLUTION: A theme is used for b .

PROBLEM: You would eat ice cream because you are depressed.

SOLUTION: You would change ice cream because you are depressed .

PROBLEM: When detonated, a nuclear weapon  produces a mushroom cloud.

SOLUTION:
When detonated , a whole tip produces a mushroom cloud .