Réponse:
He has written a letter:
negative: He has not written a letter
question: Has je written a letter ?
They have not stopped:
positive: They have stopped
question: Have they stopped ?
Have we danced?:
positive: We have danced
négative : We have not danced
She has worked:
négative: She has not worked
question: Has she worked ?
Andy has not slept:
positive: Andy has slept. question: Has Andy slept?
Voila!
