Yan Yan: That's the swallow.
Difference (cρ)pool(chí) Its feather: It means the same as "sawtooth" and describes the tail of Zhang Shuqi, a swallow.
This poem is taken from The Book of Songs Li Yan Feng Yan, which is a very beautiful lyric chapter in The Book of Songs Li Feng and a farewell poem. The poet used Yan Yan's freedom and happiness to contrast the sadness of his compatriots' separation.
Extended data:
The complete translation of this poem is as follows:
Swallows fly in the sky, spreading their wings irregularly. My sister got married today and sent her to a country road. Seeing no one, tears poured down.
Swallows are flying in the sky, and their posture is up and down. My sister is getting married today, so it won't take too long to see her off. Looking forward to seeing no one, I stood in tears.
Swallows fly in the sky, singing and whispering. My sister got married today and sent her to the south. It's really hard not to meet anyone.
The second sister is honest and steady, and her thoughts are practical and profound. Gentle and obedient, cautious and kind. I often think of my father and my ears.