"Hay un hombre en el coche."
Translation:There is a man in the car.
For me "hay" is equal not to "there is". For instans if ask for something in shop You say "Hay sellos?" translated to You say Do you have stamps?
Hay is "there is/are." So, ¿hay sellos? is actually, "Are there stamps?" which is in turn thought of in translation as, "Do you have stamps?" Of course, the latter would actually be something like, ¿Tiene sellos?, or less formally, ¿Tienes sellos?.