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

(11) And how could ye take it when ye have gone in unto each other, and they have Taken from you a solemn covenant?

(12) Except those who join a group between whom and you there is a treaty (of peace), or those who approach you with hearts restraining them from fighting you as well as fighting their own people. If Allah had pleased, He could have given them power over you, and they would have fought you: Therefore if they withdraw from you but fight you not, and (instead) send you (Guarantees of) peace, then Allah Hath opened no way for you (to war against them).

(13) If it were His will, He could destroy you, o mankind, and create another race; for He hath power this to do.

(14) And behold! Allah will say: "O Jesus the son of Mary! Didst thou say unto men, worship me and my mother as gods in derogation of Allah'?" He will say: "Glory to Thee! never could I say what I had no right (to say). Had I said such a thing, thou wouldst indeed have known it. Thou knowest what is in my heart, Thou I know not what is in Thine. For Thou knowest in full all that is hidden.

(15) If We had sent unto thee a written (message) on parchment, so that they could touch it with their hands, the Unbelievers would have been sure to say: "This is nothing but obvious magic!"

(16) If thou couldst but see when they are confronted with the Fire! They will say: "Would that we were but sent back! Then would we not reject the signs of our Lord, but would be amongst those who believe!"

(17) If thou couldst but see when they are confronted with their Lord! He will say: "Is not this the truth?" They will say: "Yea, by our Lord!" He will say: "Taste ye then the penalty, because ye rejected Faith."

(18) If their spurning is hard on thy mind, yet if thou wert able to seek a tunnel in the ground or a ladder to the skies and bring them a sign,- (what good?). If it were Allah's will, He could gather them together unto true guidance: so be not thou amongst those who are swayed by ignorance (and impatience)!

(19) Say: "Think ye, if Allah took away your hearing and your sight, and sealed up your hearts, who - a god other than Allah - could restore them to you?" See how We explain the signs by various (symbols); yet they turn aside.

(20) Who can be more wicked than one who inventeth a lie against Allah, or saith, "I have received inspiration," when he hath received none, or (again) who saith, "I can reveal the like of what Allah hath revealed"? If thou couldst but see how the wicked (do fare) in the flood of confusion at death! - the angels stretch forth their hands, (saying),"Yield up your souls: this day shall ye receive your reward,- a penalty of shame, for that ye used to tell lies against Allah, and scornfully to reject of His signs!"