The word(s) "once" appears 119 time(s) in 116 verse(s) in Quran in Abdullah Yusuf Ali translation.

(81) But he had no authority over them,- except that We might test the man who believes in the Hereafter from him who is in doubt concerning it: and thy Lord doth watch over all things.

(82) And Allah did create you from dust; then from a sperm-drop; then He made you in pairs. And no female conceives, or lays down (her load), but with His knowledge. Nor is a man long-lived granted length of days, nor is a part cut off from his life, but is in a Decree (ordained). All this is easy to Allah.

(83) (A voice will say,) "This is the Day of Sorting Out, whose truth ye (once) denied!"

(84) Can lead (any) into temptation concerning Allah,

(85) "What! has the Message been sent to him - (Of all persons) among us?"... but they are in doubt concerning My (Own) Message! Nay, they have not yet tasted My Punishment!

(86) Who, then, doth more wrong than one who utters a lie concerning Allah, and rejects the Truth when it comes to him; is there not in Hell an abode for blasphemers?

(87) The Day whereon they will (all) come forth: not a single thing concerning them is hidden from Allah. Whose will be the dominion that Day?" That of Allah, the One the Irresistible!

(88) (Allah) knows of (the tricks) that deceive with the eyes, and all that the hearts (of men) conceal.

(89) A believer, a man from among the people of Pharaoh, who had concealed his faith, said: "Will ye slay a man because he says, 'My Lord is Allah'?- when he has indeed come to you with Clear (Signs) from your Lord? and if he be a liar, on him is (the sin of) his lie: but, if he is telling the Truth, then will fall on you something of the (calamity) of which he warns you: Truly Allah guides not one who transgresses and lies!

(90) "The ways and means of (reaching) the heavens, and that I may mount up to the god of Moses: But as far as I am concerned, I think (Moses) is a liar!" Thus was made alluring, in Pharaoh's eyes, the evil of his deeds, and he was hindered from the Path; and the plot of Pharaoh led to nothing but perdition (for him).