Time Flies - 白驹过隙

白驹过隙 (bái jū guò xì)

白: white
驹: pony
过: cross, pass through
隙: chink in a wall

Literal translation: A white pony flashes past a chink in a wall.

It means "time passes quickly like a white pony's shadow across a crevice".

Corresponding English idiom: Time flies.

Example sentence: Time flies, I became 30 years old in the twinkling of an eye. (时间如白驹过隙, 转眼我已经三十岁了.)