每日翻译： 为了改善环境，中国最大的、人口最密的城市--上海，正在计划建造一座占地 300 多公顷的森林公园，称为“超级绿肺”。

为了改善环境，中国最大的、人口最密的城市--上海，正在计划建造一座占地 300 多公顷的森林公园，称为“超级绿肺”。

Shanghai, China's largest and most densely populated city, is in the process of planning a "Super Green Lung" forest park spanning more than 300 hectares.

Shanghai, the biggest and most densely populated city in China, is currently undertaking plans to construct a "Super Green Lung" forest park that will occupy an area of over 300 hectares.

优秀译文：

In order to better its environment, Shanhai, China's largest and most populous city, is planning to build a forest park spreading out over 300 hectares of land, to be known as the "Super Green Lung".