The lyrics is from The Book of Songs, the earliest collection of poems and songs in China. This is one of the most famous poems that describes the feelings of longing and pining for the loved one. And this song is written for female choir particularly. In the lyrics, the word "Qingqing" indicates the young lover who has blue collar.
青青子衿，悠悠我心。
縱我不往，子寧不嗣音？
青青子佩，悠悠我思。
縱我不往，子寧不來？
挑兮達兮，在城闕兮。
一日不見，如三月兮！
Blue-collared lad, you’ve long been in my heart.
Although I cannot go to you, couldn’t you send word to me?
Blue-belted lad, you’re in my loving thoughts.
Although I cannot go to you, couldn’t you come here to me?
I keep pacing and climbing the lookout tower of the city wall.
One day without seeing you is like three months to me.