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.