I can hardly believe you have been here--------?改为反意疑问句

楼上的朋友都没做对：

I can hardly believe you have been here，have you?

首先，hardly(几乎不)是否定词，后面用肯定式，
其次，以I believe/think 开首的句子，反意疑问句要根据从句，而本句的从句中用助动词have.

I can hardly believe you have been here ,will you?

How can I believe you have been here?

don't you?
好象是该从句的

I can hardly believe you have been here，can you？