Present Perfect. Change the sentences to negative.

1. I have called her today.

2. They have missed their chance.

3. We have worked on this together.

4. I have tried to reach him.

5. He has failed to get their attention.

6. It has been easy.

7. She has been sick lately.

8. She has put on a black dress.

9. He has exercised this week.

10. We have known each other for a long time.