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 post a message then you should have an email.

SOLUTION: If you want to find a message then you should have an email .

PROBLEM: You can summon a ninja to switch hills .

SOLUTION: You can save a goat to join hills .

PROBLEM: You would stake a tree in lawn .

SOLUTION:
You would do a tree in lawn .