Which of the verbs in bold expresses: obligation/strong recommendation? lack of obligation!necessity! permission/possibility? recommendation/advice? prohibition? What are the equivalents in your language?

obligation/strong recommendation - must, shouldn't, have to (Обязанность\настоятельная рекомендация – должен, не следует, обязан)
lack of obligation/necessity - don't have to (Отсутствие обязательности\необходимости – не обязан)
permission/possibility - can('t) (Разрешение\возможность – может (не может))
recommendation/advice - should/ought to/had better (Рекомендация совет – должен\обязан\следовало бы)
prohibition - mustn't (Запрет – не должен)