在许多发达的沿海城市,不断恶化的环境已经开始制约城市的可持续发展。为改善沿海城市的环境,荷兰研究人员设计出一种可悬浮在海洋上的人造小岛,名为“海上之树”。研究人员相信,这种小岛能够很好地解决城市里日益严重的环境污染问题,而且能成为野生动物的栖息天堂。向海洋要绿地评价一座城市的环境良好程度,一个很重要的指标就是人均绿地的面积。城市里的绿地尤其是树 In many developed coastal cities, the deteriorating environment has begun to constrain the sustainable development of the city. In order to improve the environment of the coastal cities, Dutch researchers have designed a man-made island that can be suspended on the sea and named it “The Tree of the Sea.” The researchers believe that this island can solve the growing environmental pollution problems in the city and it can become a habitat for wild animals. One of the most important indicators for assessing the degree of environmental well-being in a city is the area of ​​per capita green space. The green space in the city is especially a tree