9.55 ellipsis with 'not'

You can make the second verb group negative by adding 'not' to the auxiliary. These combinations are contracted in informal speech and writing to 'don't', 'hasn't', 'isn't', 'mustn't', and so on (see paragraph 4.55 for a list of these contractions). You use the same forms for a negative response to a question.

• Some managed to vote but most of them didn't.
• 'You're staying here!' --- 'But Gertrude, I can't, I mustn't!'
• 'And did it work?' --- 'No, I'm afraid it didn't.'
• Widows receive state benefit; widowers do not.
• He could have listened to the radio. He did not.