我又不是太阳怎么发光
[wŏ yòu bù shì tài yáng zĕn me fā guāng]
The phrase means 'I am not the sun; how can I shine?', implying modesty. It can also express a sense of powerlessness or inadequacy faced with life problems where it's felt that one isn't powerful enough or cannot emit light (bring warmth/brightness/positive impacts to the surroundings) like the sun does to everyone.