Thank you, guys.
Hi Divavocals, you are right. I made a stupid mistake. Really appreciate your patience.
I just found another question. Do you think there is any conflict between IH and zx_slideshow? I had check this again and again. IH works very well when I didn't install slideshow. After installing slideshow, something wrong happened: can't jump to IH interface through clicking on the small icon on the right column of the product in catalog/categories/product and just one category can be chosen to edit on the IH interface. (exactly the problem that we talked and I showed you a vedio before)