1.We have English classes------day,Tuesday,Thursday and Satu

答案：B.
翻译：我们每隔一天就有英语课,周二周四和周六.
1.each other意思是“相互/互相”,该短语只能单独使用,不能做定语修饰day.
如：We help each other.我们互相帮助.
2.one day的意思是“有一题/总有一天”,也是单独做时间状语,不能做定语修饰day.
如：One day I met him on the street.有一天我在大街上碰到了他.
You will succeed one day.你总有一天会成功的.
3.固定短语：every other + 名词单数,意思是“每隔一...”,刚好符合后面的语意：Tuesday,Thursday and Saturday.
再如：We plant a tree evey other meter.我们每隔一米就种一棵树.
4.综上所述,正确答案为B.