The word(s) "why" appears 68 time(s) in 63 verse(s) in Quran in Mohsin Khan translation.

(41) And those who disbelieve say: "why is not the Qur'an revealed to him all at once?" Thus (it is sent down in parts), that We may strengthen your heart thereby. And We have revealed it to you gradually, in stages. (It was revealed to the Prophet صلى الله عليه وسلم in 23 years.).

(42) He said: "O my people! why do you seek to hasten the evil (torment) before the good (Allah's Mercy)? why seek you not the Forgiveness of Allah, that you may receive mercy?"

(43) And if (We had) not (sent you to the people of Makkah) - in case a calamity should seize them for (the deeds) that their hands have sent forth, they would have said: "Our Lord! why did You not send us a Messenger? We would then have followed Your Ayat (Verses of the Qur'an) and would have been among the believers."

(44) But when the truth (i.e. Muhammad صلى الله عليه وسلم with his Message) has come to them from Us, they say: "why is he not given the like of what was given to Musa (Moses)? Did they not disbelieve in that which was given to Musa (Moses) of old? They say: "Two kinds of magic [the Taurat (Torah) and the Qur'an], each helping the other!" And they say: "Verily in both we are disbelievers."

(45) And they say: "why are not signs sent down to him from his Lord? Say: "The signs are only with Allah, and I am only a plain warner."

(46) "And why should I not worship Him (Allah Alone) Who has created me and to Whom you shall be returned.

(47) "What is the matter with you? why do you not help one another (as you used to do in the world)?"

(48) And they will say to their skins, "why do you testify against us?" They will say: "Allah has caused us to speak as He causes all things to speak: and He created you the first time, and to Him you are made to return."

(49) And if We had sent this as a Qur'an in a foreign language (other than Arabic), they would have said: "why are not its verses explained in detail (in our language)? What! (A Book) not in Arabic and (the Messenger) an Arab?" Say: "It is for those who believe, a guide and a healing. And as for those who disbelieve, there is heaviness (deafness) in their ears, and it (the Qur'an) is blindness for them. They are those who are called from a place far away (so they neither listen nor understand)."

(50) And they say: "why is not this Qur'an sent down to some great man of the two towns (Makkah and Ta'if)?"