①on his free time宜改为in his spare/free time
②for the interesting things 中的for 宜改成 about
③He practices the guitar every day,but he can’t play the guitar very well.宜改为Although he practices playing the guitar every day,he plays it not very well.
④he study English three times a week 中study的时态要用第三人称单数
如果这个是作文的话,问题比较多,简单句太多,句子与句子间的意思重复比较多,适宜添加部分从句,和灵活使用代词等等