The nickname for the city of Seattle is " emerald city."

西雅图市的昵称是“翡翠城” 。

Evergreen is a type of tree that is always green the entire year, and so, that's why they call Seattle " the emerald city, " because it's so green.

常青树是一种全年都是绿色的树，所以，这就是为什么他们称西雅图为“翡翠城” ，因为它是如此的绿色。