choose the correct verb.if both variants are correct explain the difference in meaning.
1)Some people have to/must work at night.
2)I watch TV all the time.I have to/must stop it.
3)Fidans granny is ill.She has to/must visit her.
4)Today is my little brothers birthday.I have to/must send him a card.
5)They have no English story books.Thry have to/must go to the book shop.
6)Elvin is so pale.He has to/must have some fresh air.