I always wanted to change a new schoolbag, but my parents said that the schoolbag I used now was pretty new. So I told them that if I did well in the exam, they should buy me a new one. They were happy to say yes. I studied very hard for my goal. At last, I made great progress and my parents answered my wish. 

翻譯： 我一直想換一個新的書包，但是我父母說我現在用的書包還很新。因此我跟他們說如果我考得好，他們應該給我買一個新的。他們很高興地答應了。我為我的目標努力學習，最后，我取得了很大的進步，我的父母實現了我的愿望。