when a city has about 500000 people,it is time to stop building there and to start a new city翻译
问题描述：
when a city has about 500000 people,it is time to stop building there and to start a new city翻译
答
当一个城市大约有50完居民的时候，就到了停止在那里建设而是开始去一个新城市建设的时候了。
答
当一个城市的人口达约50万时,是该停止在那里修建并开始建立一个新城市的时候了.