单句改错。 1. Please accept my congratulation on your marriage. ___________________________________________________________ 2. The Great Wall is worth of being visited. __________________________________________________________ 3. I'll do what I can to help you in return  your help. _________________________________________________________. 4. Occasions are quite rare which I have the time to spend a day with my kids. _________________________________________________________ 5. Three-fourths of the homework have been finished. _________________________________________________________ 6. Tom's mother kept telling him stories he was interested in them. _________________________________________________________ 7. Judged from his accent, he must be from America. _________________________________________________________ 8. Betty shows great interest in this poem now, but she thought it boring for the first time she read it. ___________________________________________________________ 9. When the fire broke out, many workers escaped the building. ____________________________________________________________ 10. To our great surprise, the scientist devotes all his life to observe the su n. ______________________________________________________________