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

(1) He said: "O Adam! Tell them their names." When he had told them, Allah said: "Did I not tell you that I know the secrets of heaven and earth, and I know what ye reveal and what ye conceal?"

(2) And cover not Truth with falsehood, nor conceal the Truth when ye know (what it is).

(3) Know they not that Allah knoweth what they conceal and what they reveal?

(4) Or do ye say that Abraham, Isma'il, Isaac, Jacob and the Tribes were Jews or Christians? Say: Do ye know better than Allah? Ah! who is more unjust than those who conceal the testimony they have from Allah? but Allah is not unmindful of what ye do!

(5) The people of the Book know this as they know their own sons; but some of them conceal the truth which they themselves know.

(6) Those who conceal the clear (Signs) We have sent down, and the Guidance, after We have made it clear for the people in the Book,-on them shall be Allah's curse, and the curse of those entitled to curse,-

(7) Those who conceal Allah's revelations in the Book, and purchase for them a miserable profit,- they swallow into themselves naught but Fire; Allah will not address them on the Day of Resurrection. Nor purify them: Grievous will be their penalty.

(8) O ye who believe! the law of equality is prescribed to you in cases of murder: the free for the free, the slave for the slave, the woman for the woman. But if any remission is made by the brother of the slain, then grant any reasonable demand, and compensate him with handsome gratitude, this is a concession and a Mercy from your Lord. After this whoever exceeds the limits shall be in grave penalty.

(9) But if anyone fears partiality or wrong-doing on the part of the testator, and makes peace between (The parties concerned), there is no wrong in him: For Allah is Oft-forgiving, Most Merciful.

(10) When My servants ask thee concerning Me, I am indeed close (to them): I listen to the prayer of every suppliant when he calleth on Me: Let them also, with a will, Listen to My call, and believe in Me: That they may walk in the right way.