1. Must
1.1. Obligation
1.1.1. I must finish this report by tomorrow.
1.2. Deduction
1.2.1. They must be at home now. It's already 9 PM.
1.3. Strong Recommendation
1.3.1. You must try that new restaurant. It's fantastic!
1.4. Necessity
1.4.1. You must respect others' rights.
2. Can
2.1. Present Ability
2.1.1. She can speak three languages.
2.2. Permission
2.2.1. Can I borrow your pen?
2.3. Suggestion
2.3.1. You can try adding some spices to the dish.
3. Could
3.1. Past Ability
3.1.1. When I was younger, I could run a mile in under six minutes.
3.2. Polite Request
3.2.1. Could you please pass the salt?
4. May/ Might
4.1. Probability
4.1.1. It may rain tomorrow.
4.1.1.1. It might rain tomorrow.
4.2. Permission
4.2.1. May I borrow your pen?
4.2.1.1. Might I borrow your pen?
5. Should/ Ought to
5.1. Obligation
5.1.1. You should pay your taxes on time.
5.1.1.1. We ought to respect the environment.
5.2. Advice
5.2.1. You should eat more fruits and vegetables.
5.2.1.1. You ought to consider taking a break from work. You seem stressed.
5.3. Recommodation
5.3.1. I should think you should take a break.
5.3.1.1. You ought to consider seeking professional help.
5.4. Expectation
5.4.1. The train should arrive soon.
6. Have to
6.1. Obligation
6.1.1. I have to go to work tomorrow.