1/ That must not be Harry, he always comes at 10 am.
2/ I'll not be able to come to the club tomorrow, because I have to go to the doctor.
3/ I don't think we should buy him this tie. He doesn't like the colour.
4/ This information must be useful.
5/ My brother has to walk the dog. It is his chore.
6/ Have your parents checked your homework diary.
P.S: Очень надеюсь, что это поможет. Удачи вам!