Question 1

What's the difference between 'must' and 'have to'?

Accepted Answer

'Must' usually expresses personal obligation (the speaker feels it's necessary). 'Have to' expresses external obligation (rules, laws, or someone else's authority).

Question 2

When do I use 'should'?

Accepted Answer

Use 'should' to give advice or say what is the right thing to do. It is less strong than 'must' or 'have to'.

Question 3

What is the negative form of 'must'?

Accepted Answer

The negative is 'mustn't', which means prohibition (not allowed).

Question 4

How do I say something is not necessary?

Accepted Answer

Use 'don't have to' or 'doesn't have to'. Example: 'You don't have to wear a suit.'

Question 5

What is the most common mistake with modals of obligation?

Accepted Answer

Using 'to' after a modal (e.g., 'must to go' instead of 'must go'), or confusing 'mustn't' (prohibition) with 'don't have to' (no necessity).

Question 6

How do I change 'It is necessary to' into a modal?

Accepted Answer

Use 'must' or 'have to'. Example: 'It is necessary to arrive on time' → 'You must/have to arrive on time'.

Question 7

Can I ask about specific rules?

Accepted Answer

Yes, ask about anything you're unsure about using modals like 'Do I have to...?' or 'Must I...?'.

Question 8

How will the AI check my modals?

Accepted Answer

The AI will check if you used the correct modal for the type of obligation (personal vs external, prohibition vs lack of necessity, advice).

Modals of Obligation and Prohibition: Rules at Work – Grammar B1

I _____ remember to call my mum. It's her birthday.

Modals of Obligation and Prohibition: Rules at Work – Grammar B1

I _____ remember to call my mum. It's her birthday.