过隙白驹

Explanation: Gap: gap; Baiju: originally referred to the white horse, after the analogy shadow. The same time as the horse metaphor in the small gap quickly across the front. 　　Source: "Zhuangzi knows the North Tour" life between heaven and earth, but if too Baiju of a sudden it. " 　　Examples: Brothers and a change of position is more fame and heart rate, Qi Buwen time as ~. (Yuan Ma Zhiyuan, "Jian Fu Bei" First off)