🎯 Learning Objectives
- Identify the difference between strong obligation (must/have to) and advice (should).
- Use 'must', 'have to', and 'should' to talk about rules and responsibilities at work.
- Recognize the correct form for questions and negative sentences (e.g., don't have to, mustn't).
- Demonstrate how to give and understand professional advice in a business conversation.
We use special verbs called modal verbs to talk about obligation (rules) and advice. The main ones are must, have to, and should.
Form/Structure
The structure is simple: Subject + modal verb + base verb (verb without 'to').
| Modal Verb | Use | Positive (+) | Negative (-) | Question (?) |
|---|---|---|---|---|
| must | Strong obligation, a rule (often from the speaker) | I must finish this report. | You mustn't be late. (It's forbidden) | (Rare, use 'Do I have to...?') |
| have to | Strong obligation, an external rule (company, law) | He has to wear a uniform. | You don't have to work on Saturday. (It's not necessary) | Do you have to travel for work? |
| should | Advice, a good idea, a recommendation | You should take a break. | We shouldn't rush this decision. | Should I send the email now? |
Time Expressions
These modals are used for present and future situations: today, tomorrow, this week, every day, before 5 PM.
🔑 Key Learning Tip: Remember the difference in negative forms:• mustn't = Prohibition. Don't do it! It's against the rules.
• don't have to = No obligation. It is not necessary. You have a choice.
📅 Project Deadlines: "We have to submit the project plan by Friday. This is the client's deadline."
💼 Meetings: "You should review the agenda before the meeting. It will help you prepare."
📈 Safety & Security: "You mustn't share your computer password with anyone."
🤝 Giving Advice: "Your colleague is very busy. You say, 'You should ask our manager for help.'"
📊 Reporting: "I have to update my sales report at the end of every week."
🎯 Planning Your Day: "I must call the new client today; it's my top priority."
✅ Correct Professional Usage
❌ Common Business Mistakes
Listen to Maria, a Project Manager, welcoming Leo, a new team member.
Maria and Leo conversation (approx. 2:00 minutes):
Maria: Hi Leo, welcome to the team! I'm Maria, the project manager. I want to talk about how we work on this project.
Leo: Hi Maria, great to be here. Thanks.
Maria: Of course. So, first, a few company things. You have to complete your online HR training by the end of the week. Everyone does this. Also, you have to submit your timesheet every Friday. That's a firm company rule.
Leo: Okay, HR training and timesheets. Got it.
Maria: Great. For our team specifically, there are two key things. You must attend our daily stand-up meeting at 9:15 AM. It's very important for communication. And you mustn't miss the weekly project review on Wednesdays. It's mandatory.
Leo: 9:15 AM stand-up, Wednesday review. No problem.
Maria: Perfect. Now, for some general advice. The work can be difficult sometimes. You should ask questions if you are not sure about something. Please, don't be shy. We are here to help.
Leo: That's good to know, thank you.
Maria: And you should take regular breaks. It's important not to get too tired. You don't have to work late every day. We want you to have a good work-life balance. If you finish your tasks, you can go home. You don't have to stay until 6 PM just because other people are here.
Leo: That sounds really good. Thanks, Maria. This is very helpful.
Maria: You're welcome, Leo. My final piece of advice is that you should have lunch with the team this week. It's a great way to get to know everyone.
Exercise A: Matching Exercise
Match each situation above with the correct sentence below.
Situations:
1. A strong company rule
2. A recommendation or good idea
3. A prohibition (something you cannot do)
4. It's not necessary
Sentences:
A. "You should ask for help if you need it."
B. "You don't have to wear a tie on Fridays."
C. "All visitors must sign in at reception."
D. "You mustn't leave a client waiting."
Exercise B: True/False Grammar Check
Read the sentences below. Are they grammatically correct? Choose True or False.
1. "He has to preparing a presentation for the new clients."
2. "We should check the details before we send the contract."
3. "You don't must forget to lock the door when you leave."
4. "She doesn't have to join the call if she is busy."
Exercise C: Complete the Dialogue
Fill the gaps with the correct modal verb: must, have to, should, mustn't, or don't have to.
Alex: Hi Sam, do you have a minute? I'm a bit worried about the presentation tomorrow.
Sam: Sure. What's wrong?
Alex: I'm not sure if my part is long enough. (1) _______ I add more slides?
Sam: Hmm, you (2) ________ worry too much. It looks good.
But the manager said we (3) ________ speak for more than 10 minutes each. It's a strict rule.
Alex: Oh, okay. So I (4) ________ make it longer.
Sam: Right. But you (5) ________ include a summary slide at the end. I think that's a good idea.
📋 Prepare these speaking tasks for your next class with your teacher:
Preparation for Class: Imagine you are welcoming a new person to your team. Explain three important things using must, have to, and shouldn't. Think of one company rule, one important team task, and one piece of advice.
Preparation for Class: Your partner is a colleague who is having a problem (e.g., "I have too much work," or "I don't understand the new software"). Listen to their problem and give them two pieces of advice using should and shouldn't.
Preparation for Class: Role-play a short meeting between a manager and a team member to start a new project. Manager: Explain what the team member has to do, what they must do, and what they should do to succeed.
📚 Lesson Summary for Teachers
Grammar Focus: Modal verbs 'must', 'have to', and 'should' for obligation and advice.
Key Challenge: Students often confuse the negative forms 'mustn't' (prohibition) vs 'don't have to' (no obligation), and confuse 'should' (advice) with 'have to' (obligation).
🎯 Speaking Practice Guidance
Task 1: Focus on correct use of modals for different types of rules and advice. Ensure students use base verbs after modals.
Task 2: Guide students to use 'should/shouldn't' for advice, not 'must' or 'have to'.
Task 3: Help students distinguish between company rules ('have to'), internal priorities ('must'), and recommendations ('should').
⚠️ Common Student Errors to Watch For
- Adding 'to' after the modal: "You must to go" ❌
- Using 'don't have to' for prohibition: "You don't have to smoke here" ❌
- Using 'should' for strong obligations: "You should be here at 9 AM" (when it's a company rule) ❌
🎯 Professional Key Takeaways:
Must: For strong personal obligations and rules you enforce (I must call the client today).Have to: For external obligations, company rules, and requirements (We have to submit reports by Friday).
Should: For advice, recommendations, and good ideas (You should take a break).
Negative forms: 'Mustn't' = forbidden, 'Don't have to' = not necessary.
Structure: Always use modal + base verb (e.g., must go, have to see, should finish). No "to" after the modal.