I have a new friend from Macedonia who is learning English. Can you imagine explaining the above examples to her?

I think this was the point of the thread. When do we use articles and when don't we? The Russian language has no articles, for example. Portuguese has the same ones we do, but they're used differently in that language. Cross-street and open-door aren't really to the point here, one being a noun and the other an adjective. [/clarification]