How long has the shop__.A,been open.B been opened 答案是B为什么

问题描述:

How long has the shop__.A,been open.B been opened 答案是B为什么

open 做形容词是“开着的”,如果提问,应该直接用系动词问:
How long is the shop open?
这里open是动词,“开门”,所以用完成时态.