天空不懂向日葵的忧伤
[tiān kōng bù dŏng xiàng rì kuí de yōu shāng]
'Tian Kong Bu Dong Xiang Ri Kui De You Shang' means 'the sky doesn't understand the sorrow of sunflowers'. This is a metaphor expressing feelings of isolation or not being understood; like sunflowers turning toward sunlight but the source of their life can't reciprocate those actions.