" When I come out after a thousand calls, I still hold the pipa and cover my face halfway." This was a poem from Bai Juyi's " Farewell to Ancient Grass " of the Tang Dynasty. After a long time of calling and summoning, he finally showed up with a half-covered smile. It was a metaphor for a person who hid his shortcomings or inadequacies, or deliberately kept his secrets and was unwilling to show his strength publicly. It could also be understood as having a chance to show off after a long wait, but the performance was still insufficient and needed more effort and tempering. This phrase is often used to describe something that gradually appears after a long wait, such as waiting for someone, the result of something, or waiting for the arrival of some good news.