10. 2-could. 3-can. 4-Does. 5-Could. 6-have to do. 7-couldn't. 8-don't.
11. 2- l could ride a bike when I was four yeas old. 3- We can go to the party tomorrow. 4- You mustn't be late for school. 5-Becky has to look after her lettle sister today. 6-Could you run when you were two years old? 7-Do you have to tidy your bedroom? 8-He doesn't have to help his dad today.