The word(s) "could" appears 105 time(s) in 97 verse(s) in Quran in Abdullah Yusuf Ali translation.

(61) If (such) were Our Will, We could send down to them from the sky a Sign, to which they would bend their necks in humility.

(62) "Their account is only with my Lord, if ye could (but) understand.

(63) Then We caused the earth to swallow up him and his house; and he had not (the least little) party to help him against Allah, nor could he defend himself.

(64) And those who had envied his position the day before began to say on the morrow: "Ah! it is indeed Allah Who enlarges the provision or restricts it, to any of His servants He pleases! had it not been that Allah was gracious to us, He could have caused the earth to swallow us up! Ah! those who reject Allah will assuredly never prosper."

(65) (Remember also) Qarun, Pharaoh, and Haman: there came to them Moses with Clear Signs, but they behaved with insolence on the earth; yet they could not overreach (Us).

(66) If only thou couldst see when the guilty ones will bend low their heads before their Lord, (saying:) "Our Lord! We have seen and we have heard: Now then send us back (to the world): we will work righteousness: for we do indeed (now) believe."

(67) If We had so willed, We could certainly have brought every soul its true guidance: but the Word from Me will come true, "I will fill Hell with Jinns and men all together."

(68) See they not what is before them and behind them, of the sky and the earth? If We wished, We could cause the earth to swallow them up, or cause a piece of the sky to fall upon them. Verily in this is a Sign for every devotee that turns to Allah (in repentance).

(69) The Unbelievers say: "We shall neither believe in this scripture nor in (any) that (came) before it." couldst thou but see when the wrong-doers will be made to stand before their Lord, throwing back the word (of blame) on one another! Those who had been despised will say to the arrogant ones: "Had it not been for you, we should certainly have been believers!"

(70) But We had not given them Books which they could study, nor sent messengers to them before thee as Warners.