光阴似箭 (guāng yīn sì jiàn)

time flies like an arrow (idiom); How time flies!

Character breakdown

Usage

光阴似箭,转眼间我们已经毕业十年了。

Time flies like an arrow; in the blink of an eye, we've already graduated for ten years.

Guāngyīn sì jiàn, zhuǎnyǎn jiān wǒmen yǐjīng bìyè shí nián le.