: You should go to the doctor.
2. Must: You're a Sci-Wi fan, you must see the new Star Wars.
3. Have to/Has to don't have to/doesn't have to
- UK students always have to wear a uniform to school.
- She has to pass her exams this year to work in the USA.
- I don't have to cycle to school anymore, I have a car now.
4. Ought to: A car ought to have an annual check up to be safe.