Answer for exercise 29.1

1. She might be in her office.
2. She might be busy.
3. She might be working.
4. She might want to be alone.
5. She might have been ill yesterday.
6. She might have gone home early.
7. She might have had to go home early. 
8. She might have been working yesterday .
9. She might not want to see me.
10. She might not be working today.
11. She might not have been feeling well yesterday. 

You can use may instead of might in all these sentences.