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

(31) But Allah was not going to send them a penalty whilst thou wast amongst them; nor was He going to send it whilst they could ask for pardon.

(32) If thou couldst see, when the angels take the souls of the Unbelievers (at death), (How) they smite their faces and their backs, (saying): "Taste the penalty of the blazing Fire-

(33) And (moreover) He hath put affection between their hearts: not if thou hadst spent all that is in the earth, couldst thou have produced that affection, but Allah hath done it: for He is Exalted in might, Wise.

(34) If there had been immediate gain (in sight), and the journey easy, they would (all) without doubt have followed thee, but the distance was long, (and weighed) on them. They would indeed swear by Allah, "If we only could, we should certainly have come out with you": They would destroy their own souls; for Allah doth know that they are certainly lying.

(35) If they could find a place to flee to, or caves, or a place of concealment, they would turn straightaway thereto, with an obstinate rush.

(36) Those who were left behind (in the Tabuk expedition) rejoiced in their inaction behind the back of the Messenger of Allah: they hated to strive and fight, with their goods and their persons, in the cause of Allah: they said, "Go not forth in the heat." Say, "The fire of Hell is fiercer in heat." If only they could understand!

(37) It was not fitting for the people of Medina and the Bedouin Arabs of the neighbourhood, to refuse to follow Allah's Messenger, nor to prefer their own lives to his: because nothing could they suffer or do, but was reckoned to their credit as a deed of righteousness,- whether they suffered thirst, or fatigue, or hunger, in the cause of Allah, or trod paths to raise the ire of the Unbelievers, or received any injury whatever from an enemy: for Allah suffereth not the reward to be lost of those who do good;-

(38) Nor could they spend anything (for the cause) - small or great- nor cut across a valley, but the deed is inscribed to their credit: that Allah may requite their deed with the best (possible reward).

(39) Nor should the Believers all go forth together: if a contingent from every expedition remained behind, they could devote themselves to studies in religion, and admonish the people when they return to them,- that thus they (may learn) to guard themselves (against evil).

(40) He said: "Would that I had power to suppress you or that I could betake myself to some powerful support."