铅笔描不出彩色的天蜡笔绘不出灰色的地
[qiān bĭ miáo bù chū căi sè de tiān là bĭ huì bù chū huī sè de dì]
A pencil can't sketch out a colorful sky and crayons cannot draw a gray land. This metaphorically describes feelings of sadness and longing, juxtaposing contrasting elements (like pencils and crayons, colors vs. grayscale) while pointing to unfulfilled desires or the inability to realize dreams.