Modal verbs: must

This is the last in my series on modal verbs for now. There are nine modals in the series and you can find the rest here.

We use "must" to talk about:
1. Rules and instructions
Drivers must wear seat belts.
Students must not talk during the exam.
2. Obligation and necessity
These plants must be watered regularly.
You must tell the truth.
3. Strong advice
You really must lose some weight.
You must read this book. It's amazing!
4. Definite intentions
I must phone my mother tonight.
We must get on and book our holiday!
5. Very likely or certain
I haven't seen him today. He must be out.
You must be tired after your long journey.