假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文．文中共有5处语言错误，每句中最多有一处错误．
增加：在缺词处加一个漏字符号（
），并在其下面写出该加的词．
删除：把多余的词用斜线（\）划掉．
修改：在错的词下画一横线，并在该词下面写出修改后的词．
注意：1． 每处错误及其修改均限一词；
2．只允许修改5处，多者（从第6处起）不计分．
I am very busy on Friday． At 8：00 I have math． It is not fun． The teacher say it is useful， but I think it is difficult． Then at 9：00 I have science． It is difficult and interesting． At 10：00 I have history． After that， I have P．E． at 11：00． It is easy and fun． Lunch is 12：00 to 1：00， and after that we have Chinese． It's I favorite subject． Our Chinese teacher ， Mrs． Wang， is great fun． My classes are finish at 1：50， but after that I have an art lesson for two hours． It is really relaxing．