не пробовали сменить ориентацию (текста)
A. 1) must be polite
2) mustn't touch
3) don't have to buy
4) must visit
5) have to go
6) doesn't have to walk
7) don't have to learn
B. если проверяют только must и have to, то так (в противном случае, в некоторых предложениях лучше сказать по-другому)
1. You shouldn't go outside. it's cold there.
2. Little children mustn't eat ice cream.
3. I must help my friend.
4. You won't have to sleep on the floor. We have got a bed for guests
5.You must buy a ticket
6.He doesn't have to see a doctor. Her mother is a doctor.
7.They mustn't sit on the floor. The floor's dirty.
8.He mustn't lose the key, We've got only one.