上课铃声是催眠曲下课铃声是兴奋剂
[shàng kè líng shēng shì cuī mián qŭ xià kè líng shēng shì xīng fèn jì]
Translates as 'The school bell is a lullaby; the end-of-class bell is a stimulant.' This reflects the experience many students share of feeling drowsy during class but suddenly alert when it's time for a break. It’s a relatable statement about the daily rhythm of student life.