一个人守着一座城一座城等着一个人
[yī gè rén shŏu zhe yī zuò chéng yī zuò chéng dĕng zhe yī gè rén]
One person guards a city, a city awaits one person. Suggests loneliness and devotion where someone waits persistently even as circumstances make them solitary and isolated, often conveying longing or hope.