The class which you have selected belongs to 'Grouping classes', You have selected class from group 'D28', whereas you are already selected classes belongs to group 'D06' laying in your shopping trolley. Please choose the another class from group D06 * تطلع هذه الرساله اذآ جيت اختار ماده علم اجتماع وانا ابيهآ ' الي عندهآ خلفيه تقول لي الله يجزاهآ الجنه