帮我看看下面的作文有什么语法方面的错误并纠正,如果20分的作文这篇可以给多少分?
IjustcamebackBeijinglastweek.ItisaverybeautifulcitythatIvisiteditonJuly22thtoJuly26thwith15studentsfromdifferentschool.Wevisitedmanyplacesofinterest,suchastheGreatWall,thePalaceMuseum,theSummerPalaceandseveralfamousuniversity.MyfavoriteplaceisPekingUniversitywhichitismydreamschoolsothatIencouragemetostudyhard.ThebestthingthatImadeverynewfriendsofthattravel.Butbecauseofthehotweather,Ifeltuncomfortable.Whatapity!Butinawordthatthetravelwasfullofinteresting.