They not understand me.
They don't understand me.
I not go to school on Sunday.
I don't go to school on Sunday.
His granny don't like computer games.
His granny doesn't like computer games.
Tom doesn't plays tennis every day.
Tom doesn't play tennis every day.
We don't know this girl.
Correct!
My brother doesn't studies French.
My brother doesn't study French.
My mother don't like shopping.
My mother doesn't like shopping.
Their dogs doesn't like cats.
Their dogs don't like cats.
My cat do not like fish.
My cat doesn't like fish.