What's lost is lost. 失者不可復得。

What's done cannot be undone. 生米煮成熟飯了。

What is learned in the cradle is carried to the grave. 兒時所學，終生難忘。

Whatever you do, do with all your might. 不管做什麼，都要一心一意。

Wet behind the ears. 乳臭未乾。

We should never remember the benefits we have offered nor forget the favor received. 自己的好事別去提，別人的恩惠要銘記。

We shall never have friends if we expect to find them without fault. 欲求完美無缺的朋友必然成為孤家寡人。

We never know the worth of water till the well is dry. 井干方知水可貴。

Well begun is half done. 好的開始，是成功的一半。

We know not what is good until we have lost it. 好東西，失去了才明白。