该句使用比喻结构，将青春比作奔流的河水表达时间不可逆。
Youth is like a rushing river, never to return.
In our childhood,
A bright, innocent smile graced our faces. Holding windmills, we ran through verdant lawns with our parents following closely behind. Sweat would bead on our foreheads unnoticed. There were no worries, no sorrows.
In our teenage years,
We walked home with classmates, backpacks on our shoulders, humming the latest rock songs. When we were sad, friends shared our sorrows; when we were happy, we shared our joys. Slowly, we matured and grew up.
In adulthood,
Full of dreams, we stepped out of university, eager to carve out a bright future. Gradually, we acquired a car and a house; we transformed from naive newcomers into seasoned professionals. Our homes evolved from a duo to a family of three. Life was filled with happiness and tranquility.
And now,
A few silver strands appear at our temples, and our health is not what it used to be. Having retired from the professional world, seeing our children grow up—it feels as if we are seeing ourselves in their youth. My heart is at peace, without regrets. As the sun sets, life feels serene.
Farewell, youth. Looking back at the past, I am filled with emotion. Time flies like a galloping horse; in a flash, half of life has passed. Only youth remains in my memories.
Farewell, youth.
青春如奔流的江河，一去不复返。
儿时的我们，脸上挂着天真烂漫的笑容，手里拿着风车，在翠绿的草坪上尽情奔跑，身后是紧随其后的父母。汗水悄然滑落，那时的我们，无忧无虑，没有哀愁。
少年的我们，背着书包与同学结伴走在回家的路上，嘴里不时哼着最新的摇滚乐。有忧愁时，有朋友分担；有欢乐时，与伙伴分享。在岁月的洗礼下，我们逐渐成熟，慢慢长大。
成年的我们，满怀梦想走出校门，渴望在社会上闯出一片天地。随着岁月的流逝，我们有了车，有了房，从职场新人蜕变为独当一面的高手；家庭也从最初的二人世界，变成了温馨的三人小家。生活充满了幸福，流露着恬静。
而如今，鬓边已现几缕银丝，身体也不复当年。从职场退下来，看着孩子也渐渐长大，仿佛看到了年轻时的自己，内心唯有欣慰，毫无遗憾。夕阳西下，岁月静好。
再次回望青春，感慨万千。时间如白驹过隙，转眼已过半生，唯有那段青春岁月，永远刻在心底。
再见，青春。