Ответ:

1. I have changed my email address

2. My boyfriend hasn`t worked abroad

3. Have you decided what to do?

4. They haven`t passed the exam

5. Has he accepted the invitation

6. She has studied three languages

7. The train hasn`t arrived

8. Have the children tidied their room

9. My girlfriend hasn`t phoned me

10. My father has helped me a lot