Mum, may I buy an ice-cream? (можно)
You can hear this song everywhere, it’s very popular. (можешь)
Can you believe it? I’m sure it’s nonsense. (неужели можно)
You must not read in bed. (нельзя)
You should not worry. All is going to be fine. (не нужно)
If you can afford this car, buy it. (можешь)
He must give up smoking after a heart attack. (должен)
May I help you with this heavy box? (можно)