Green space facilities are contributing to an important extent to the quality of the urban environment. Fortunately it is no longer necessary that every lecture or every book about this subject has to start with the proof of this idea. (46)At present it is generally accepted , although more as a self-evident statement than on the basis of a closely-reasoned scientific proof. The recognition of the importance of green space in the urban environment is a first step on tile right way. (47)This does not mean, however, that sufficient details are known about the functions of green space in towns and about the way in which the inhabitants are using these spaces. As to this rather Complex subject I shall, within the scope of this lecture, enter into one aspect only, namely the recreative function of green space facilities.
(48) 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, whereas there was relatively little attention for improvement of recreative possibilities in the direct neighborhood of the home. (49)We have come to the conclusion that this is not right, because an important part of the time which we do not pass in sleeping or working, is used for activities and around home. So it is obvious that recreation in the open air has to begin at the street door of the house.
(50)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 tile 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.
(49)We have come to the conclusion that this is not right, because an important part of the time which we do not pass in sleeping or working, is used for activities and around home
参考答案：
[参考译文] 我们已经得出结论，这样做是不对的，因为除了睡觉和工作所用的时间以外，我们很重要的一部分时间是用来在家里或者家的周围进行活动的。
解析：
句子框架是We have come to the conclusion…because…。because引导原因状语从句修饰主句。主句中又有that引导的同位语从句作conclusion的同位语。because引导的原因状语从句中又嵌套了一个which引导的定语从句修饰the time。