改错题。句子中有一处是有错误的，把它找出来并改正。

①There are many people are playing basketball there.____ 
②Could you tell me the different between the two books.____ 
③It was my grandpa's eighty birthday yesterday._____ 
④Bady,it's very lazy for you to sleep late every morning.____ 
⑤I wrote an 800-word's composition yesterday.____ 
⑥The fish we caught is still living.____ 
⑦The Great Wall is one of the most famous building all over the world.____ 
⑧If Tom will study hard this term,he will catch up with his classmates.____ 

【猜想与假设】①是CH₄； ②是CH₄和CO₂的混合气体

              ③是CO和CO₂的混合气体。

【实验和推断】将A中的气体依次通入B、C中，在D处点燃。