将所给句子中的一处错误写出并改正。

1. There are many people are playing basketball.                                 _______________

2. Could you tell me the different between the two books?                   _______________

3. It was my grandpa's eighty birthday yesterday.                                  _______________

4. Bady,it's very lazy for you to sleep late every morning.                       _______________

5. I wrote an 800-word's composition yesterday.                                   _______________

6. The fish we caught is still living.                                                           _______________

7. The Great Wall is one of the most famous building all over the world.   _______________

8. If Tom will study hard this term, he will catch up with his classmates.  _______________

社会主义的不发达阶段主要表现为什么？