Rain and cloud
It's a Chinese idiom. Its pronunciation is y ǔ f ù y ú NF ā n, which means the metaphor is changeable. It's from niannujiao, a nine day feeling by Tao Zongyi of Ming Dynasty.
The origin of Idioms
Tao Zongyi of the Ming Dynasty wrote a poem in niannujiao, a feeling of nine days: "yellow flowers and white hair, but also in a hurry to celebrate the festival, feeling the past and the present. The rain and the clouds are endless, and the old country is cold and hazel
Idiom usage
Used as an object or attribute; used in writing.
Rain and cloud
full of empty phrases on a scrap of paper - mǎn zhǐ kōng yán
messengers of the gods and spirits - shén chāi guǐ shǐ
load one's pages with references - páng zhēng bó yǐn
a piece of work embodying one 's utmost effort - liáng gōng kǔ xīn