单项选择，从A、B、C中选出最佳的答案。
1）— Mum, _____ I play computer games?
— Yes, you can. But you have to finish your homework first.
A. must B. can C. need
2）— Must I go and do it now?
— No, you _____. We still have two more days.
A. shouldn't B. can't C. needn't