bù / zhī / bù / jué / dà / xué / sì / nián / yǐ / rú / bái / jū / guò / xì / bān / cōng / cōng / guò / qù

不知不觉，大学四年已如白驹过隙般匆匆过去。

Before I knew it, my four years at university had passed in the blink of an eye.