Ⅰ. Choose the correct modal verbs and complete the sentences.
1. You need/needn't do all the task alone—our team will share the work together.
2. When others are talking in the team, you had better/had better not cut in—it's not polite.
3. When working in a team, we should/shouldn't help each other if someone is in trouble.
4. We have to/don't have to finish the first part of the task by Friday, or we can't do the next step.
5. As a team member, you must/mustn't be late for our group meetings—it will slow down our work.

Ⅰ. 1. needn't 2. had better not 3. should 4. have to 5. mustn't

Ⅱ. Choose the correct modal verbs and complete the conversations.
Jack:I think we 1. should / must work together to clean the park.
Stella:But I have homework. Maybe we 2. must / could finish it next week?
Jack:No, the event is tomorrow. We 3. have to / had better divide the work now.
Lily:The school notice says all students 4. have to / must wear uniforms on Monday for the singing competition.
Tom:But my mom washed mine yesterday and it's still wet. 5. Could / Need I borrow yours?
Lily:Yeah, the rule is strict—we really 6. shouldn't / needn't break it.
Teacher:The flu is going around. You 7. should / have to wash your hands often and wear a mask in class.
Student:Do I need to stay home if I have a cough?
Teacher:No, you 8. mustn't / needn't — but you 9. mustn't / needn't share cups with others.

Ⅱ. 1. should 2. could 3. have to 4. must 5. Could 6. shouldn't 7. should 8. needn't 9. mustn't