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

(31) The Messenger's duty is but to proclaim (the message). But Allah knoweth all that ye reveal and ye conceal.

(32) They say: "Why is not an angel sent down to him?" If we did send down an angel, the matter would be settled at once, and no respite would be granted them.

(33) Yea, in their own (eyes) will become manifest what before they concealed. But if they were returned, they would certainly relapse to the things they were forbidden, for they are indeed liars.

(34) Say: "If what ye would see hastened were in my power, the matter would be settled at once between you and me. But Allah knoweth best those who do wrong."

(35) No just estimate of Allah do they make when they say: "Nothing doth Allah send down to man (by way of revelation)" Say: "Who then sent down the Book which Moses brought?- a light and guidance to man: But ye make it into (separate) sheets for show, while ye conceal much (of its contents): therein were ye taught that which ye knew not- neither ye nor your fathers." Say: "Allah (sent it down)": Then leave them to plunge in vain discourse and trifling.

(36) And come not nigh to the orphan's property, except to improve it, until he attain the age of full strength; give measure and weight with (full) justice;- no burden do We place on any soul, but that which it can bear;- whenever ye speak, speak justly, even if a near relative is concerned; and fulfil the covenant of Allah: thus doth He command you, that ye may remember.

(37) Ask them concerning the town standing close by the sea. Behold! they transgressed in the matter of the Sabbath. For on the day of their Sabbath their fish did come to them, openly holding up their heads, but on the day they had no Sabbath, they came not: thus did We make a trial of them, for they were given to transgression.

(38) When thy Lord drew forth from the Children of Adam - from their loins - their descendants, and made them testify concerning themselves, (saying): "Am I not your Lord (who cherishes and sustains you)?"- They said: "Yea! We do testify!" (This), lest ye should say on the Day of Judgment: "Of this we were never mindful":

(39) They ask thee concerning (things taken as) spoils of war. Say: "(such) spoils are at the disposal of Allah and the Messenger: So fear Allah, and keep straight the relations between yourselves: Obey Allah and His Messenger, if ye do believe."

(40) Disputing with thee concerning the truth after it was made manifest, as if they were being driven to death and they (actually) saw it.