1. Jack may be upset. I can't really tell if he is annoyed or tired.

2. Jack may have been upset. I couldn't really tell if he was annoyed or tired.

3. Jack may get upset if you don't tell him the truth.

4.You may take my dictionary if you need it.

5. You may not park here. 

6. They may come any minute! 

7. It may rain tomorrow. 

8. He may be a student though I'm not sure. 

9.You may leave the table when you finish your dinner. 

10.May I call you?

11.Where may we go in the evening? 

12.He may be ill

13.It may be too expensive

14.You may buy food in the shop 

15.Tickets may be ordered beforehand