Điền must/ mustn't/ don't have to/ doesn't have to/ have to/ has to vào chỗ trống sao cho phù hợp: 1. You ... worry about her! She's all right now! 2. He's very il, he ... stay in bed. 3. Children ... play in this dangerous place. 4. We are on Saturday! We ... to get early! 5. You ... forget your dictionary for the exam! 6. Old people ... be helped. 7. You ... forget your dictionary for the exam! 8. She ... choose if she doesn't want to! 9. They are happy because they ... wear a uniform in their new school. 10. The river is too deep, you ... swim here! Giải giúp em với ạ?