由于中国人口约占世界人口的五分之一，届时，它将成为世界上最大的社会保障体系。的翻译：As China's population of about one-fifth of the world's population, by which time it will become the world's largest social security system. 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

As China's population accounts for about one-fifth of the world's population, then, it will become the world's largest social security system.

As China's population of about one-fifth of the world's population, by which time it will become the world's largest social security system.

The government proposed that, to 2020, must establish basically covers the city and countryside inhabitant's social security system

Because of China's population is about 5% of the world's population, and it will become one of the world's largest social security system.

As China's population of about one-fifth of the world's population, by which time it will become the world's largest social security system.