Khoanh tròn lựa chọn đúng trong mỗi câu.
a. Poor lan, he isn't feeling well this morning. He has to / needn't stay in bed.
b. When I go camping with my cousins next July, I must/ will have to cook.
c. You've been driving all day. You must / will have to be very tired.
d. Children mustn't/ don't have to touch the oven (bếp lò); it can be dangerous.