I have no （class还是classes）?

We have no (class/classes) on Sundays. Because I have no classes . don't have class还是classes I have no classes on w （急!） 上课是用 have class还是have classes ?Because I have no classes .怎样写?急! "class begin"还是"classes begin"? after class 还是 after classes I have four classes are A.M 还是I have four classes in A.M I have six classes a day.还是 I am six classes a d I have computer class and art classes.I like them very much. They have no classes on Saturday（改为同义句）