Dear Robert,
I promised you to go to the movie this weekend,but I can't.I am terribly sorry.
The reson is as follows.Because I was hurt when I was playing basketball with my classmates this afternoon.The doctor told my leg was broken.So I must had to rest in bed for a period of time.So I can't go to the appointment.
I hope to make an appointment next time.I'm looking forward to seeing you.Have a nice weekend.
Yours,LiHua