I an really sorry,[ ]I can not go shopping with you this Sunday.A.so B.and C.or D.but求原因

问题描述:

I an really sorry,[ ]I can not go shopping with you this Sunday.
A.so B.and C.or D.but
求原因

D,这是I’m sorry,but。。。的句型,固定搭配。类似的有,Excuse me,but。。,是习惯用语
祝楼主更上一层楼

but,在此解释为因为

I am really sorry,[ but ]I can not go shopping with you this Sunday
看句意;我感到很抱歉,这周日我不能陪你去逛商场了
中间出现了句意转折,所以用但是:but
这和语法没什么关系