摘要
城市的空气处于亚环境状态,又脏又热。对于空气污染和高温这两个紧密相关的问题,种树可能是一种解决方法。不过,为了能有效地给一个地区降温,必须大量种植树木。不幸的是,并不是所有的城市都那么幸运,能够打造公园,有些城市甚至都没有足够数量的装饰性行道树。
City air is in a sorry state.It is dirty and hot.A possible answer to the twin problems of pollution and heat is trees.To cool an area effectively,though,trees must be planted in quantity.Unfortunately,not all cities are blessed with parks or even ornamental street trees in sufficient numbers.
