Paulq I am sorry. I am vexing you a question you asked is irritating me. Of course I see shops with open and closed signs - why do you ask?
Why have not you used why did you askinstaed of why do you ask ?
Is this the difference between A.E and B.E?
Yes, there is often a sign on the door which says OPEN on one side and CLOSED on the other, and you can turn it around after opening and before closing the shop.
The point is, it says OPEN, not OPENED.
In a passive sentence, "The door was opened by Fred", this tells us who opened it, or that it has been opened, and that after this happened, the door was then open.
Here open is an adjective telling us the state of the door, but opened is a past participle, telling us what action took place.
When you are making a statement about the state of the door/room/shop, particularly over the course of a period of time, you have to use the adjective.
Oh, having just seen your later post, I see where your confusion lies. The problem is that the past participle of the verb "to close" is "closed", but the corresponding adjective of state is also "closed". That's just coincidence. Unfortunately when you see "closed" you don't know (except from context) whether it's an adjective or a participle. With "open" or "opened" you can tell the difference immediately even without context.
Furthermore, you might explain why you ask a question and then insist you already know the proper answer after being told by one or more educated, mainstream, native English speakers that you are wrong.
No, I didnt know the answer before
I just saw Bob marley quote in which closed and open is used and then I made it my signature. sir please dont mind.
and the question which I asked form PaulQ of the door was in the same manner to know more about use of open and closed.
I am again sorry If I made anyone felt bad.