Shanghai now densest city in China.

上海是中国人口最密集城市。

The coastal zone is the densest human activity zone.

海岸带是人类活动最集中的地带。

Earth is the densest of all of these remaining planets.

地球是所剩下行星中最致密的星球。

Francium is the densest of the Alkali Metals and also radioactive.

钫是碱金属中密度最大的，具有放射性。

One of the densest exoplanet to date is a world known as COROT-exo-3b.

根据数据，密度最大的外行星是一颗叫做COROT-exo-3b的行星。