The theoretical separation of living, working, traffic and recreation which for many years has been used in town-and-country planning, has in my opinion resulted in disproportionate attention for forms of recreation far from home, whether there was relatively little attention for improvement of recreative possibilities in the direct neighborhood of the home. We have come to the conclusion that this is not right, because an important past of the time which we do not pass in sleeping or working, is used for activities at and around home. So it is obvious that recreation in the open air has to begin at the street-door of the house. The urban environment has to offer as many recreation activities as possible, and the design of these has to be such that more obligatory activities can also have a recreative aspect.
The very best standard of living is nothing if it is not possible to take a pleasant walk in the district, if the children cannot be allowed to play in the streets, because the risks of traffic are too great, if during shopping you can nowhere find a spot for enjoying for a moment the nice weather, in short, if you only feel yourself at home after the street-door of your house is closed after you.
According to the author, the importance of green-spaces in the urban environment ______.

A. is still unknown
B. is usually neglected
C. is being closely studied
D. has been full recognized