短文改错（本题有10小题，每小题1分，共10分）
Dear Mum and Dad,
I expect you are surprised at hearing from me so soon.
The fact is I can’t come home this Saturday 76.
as I plan. I have had an accident and hurt my 77.
back, and it is not serious. What happened was 78.
this. I was riding in the street with Mike when 79.
I felt down and lay on my back. I thought it a .80
great joke at the first. But when I tried to stand up, 81.
I felt a pain on my back and could hardly move. 82.
Don’t worry about me. Mike and his family is 83.
so kind to me. I will better soon and there is no need 85.
for you to come there. I will write to you again soon. 85.