Well, don't is used when the subject is in present tense, and wasn't used in past tense.
no you didnt
we dont know
i dont knoe hahahahhahahah
i am Appalled at how you dont know the answer
i dont know can you
you dont know it dummy
i sliced a apple in two but i dont know how to use bisect in a sentence
You just did but, " It is very uncommon that he didnt go to work today."
i dont know the answer
I Dont freakin NO =)
easy , you dont you fool
dont have a clue at all