噬臍何及　

◎ 噬臍何及 shìqí-héjí

[useless to regret;repent too late as one who is unable to bite one‘s navel] 噬:咬;及;到。當(dāng)后悔時(shí),像用嘴咬不著自己的肚臍那樣,沒有用的。后來就用“噬臍何及”比喻后悔也來不及