The word(s) "know" appears 656 time(s) in 561 verse(s) in Quran in Abdullah Yusuf Ali translation.

(291) No knowledge have they of such a thing, nor had their fathers. It is a grievous thing that issues from their mouths as a saying what they say is nothing but falsehood!

(292) Such (being their state), we raised them up (from sleep), that they might question each other. Said one of them, "How long have ye stayed (here)?" They said, "We have stayed (perhaps) a day, or part of a day." (At length) they (all) said, "Allah (alone) knows best how long ye have stayed here.... Now send ye then one of you with this money of yours to the town: let him find out which is the best food (to be had) and bring some to you, that (ye may) satisfy your hunger therewith: And let him behave with care and courtesy, and let him not inform any one about you.

(293) Thus did We make their case known to the people, that they might know that the promise of Allah is true, and that there can be no doubt about the Hour of Judgment. Behold, they dispute among themselves as to their affair. (Some) said, "Construct a building over them": Their Lord knows best about them: those who prevailed over their affair said, "Let us surely build a place of worship over them."

(294) (Some) say they were three, the dog being the fourth among them; (others) say they were five, the dog being the sixth,- doubtfully guessing at the unknown; (yet others) say they were seven, the dog being the eighth. Say thou: "My Lord knoweth best their number; It is but few that know their (real case)." Enter not, therefore, into controversies concerning them, except on a matter that is clear, nor consult any of them about (the affair of) the Sleepers.

(295) Say: "Allah knows best how long they stayed: with Him is (the knowledge of) the secrets of the heavens and the earth: how clearly He sees, how finely He hears (everything)! They have no protector other than Him; nor does He share His Command with any person whatsoever.

(296) So they found one of Our servants, on whom We had bestowed Mercy from Ourselves and whom We had taught knowledge from Our own Presence.

(297) "O my father! to me hath come knowledge which hath not reached thee: so follow me: I will guide thee to a way that is even and straight.

(298) "Lord of the heavens and of the earth, and of all that is between them; so worship Him, and be constant and patient in His worship: knowest thou of any who is worthy of the same Name as He?"

(299) And certainly We know best those who are most worthy of being burned therein.

(300) If thou pronounce the word aloud, (it is no matter): for verily He knoweth what is secret and what is yet more hidden.