The word(s) "could" appears 96 time(s) in 90 verse(s) in Quran in Mohsin Khan translation.

(41) And he had no group of men to help him against Allah, nor could he defend (or save) himself.

(42) Then they both proceeded, till, when they came to the people of a town, they asked them for food, but they refused to entertain them. Then they found therein a wall about to collapse and he (Khidr) set it up straight. [Musa (Moses)] said: If you had wished, surely, you could have taken wages for it!"

(43) "And as for the wall, it belonged to two orphan boys in the town; and there was under it a treasure belonging to them; and their father was a righteous man, and your Lord intended that they should attain their age of full strength and take out their treasure as a mercy from your Lord. And I did them not of my own accord. That is the interpretation of those (things) over which you could not hold patience."

(44) So they [Ya'juj and Ma'juj (Gog and Magog)] could not scale it or dig through it.

(45) (To) those whose eyes had been under a covering from My Reminder (this Qur'an), and who could not bear to hear (it).

(46) "Then verily, we can produce magic the like thereof; so appoint a meeting between us and you, which neither we nor you shall fail to keep, in an open place where both shall have a just and equal chance (and beholders could witness the competition)."

(47) Did they not see that it could not return them a word (for answer), and that it had no power either to harm them or to do them good?

(48) Had We intended to take a pastime (i.e. a wife or a son), We could surely have taken it from Us, if We were going to do (that).

(49) But the chiefs of his people who disbelieved said: "He is no more than a human being like you, he seeks to make himself superior to you. Had Allah willed, He surely could have sent down angels. Never did we hear such a thing among our fathers of old.

(50) Have you not seen how your Lord spread the shadow. If He willed, He could have made it still - But We have made the sun its guide (i.e. after the sunrise, the shadow shrinks and vanishes at midnoon and then again appears in the afternoon with the decline of the sun, and had there been no sunlight, there would have been no shadow).