The word(s) "but" appears 1287 time(s) in 1137 verse(s) in Quran in Mohsin Khan translation.

(251) but those who reject Our Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.), the torment will touch them for their disbelief (and for their belying the Message of Muhammad صلى الله عليه وسلم). [Tafsir Al-Qurtubi].

(252) Say (O Muhammad صلى الله عليه وسلم): "I don't tell you that with me are the treasures of Allah, nor (that) I know the Unseen; nor I tell you that I am an angel. I but follow what is revealed to me." Say: "Are the blind and the one who sees equal? Will you not then take thought?"

(253) Say (O Muhammad صلى الله عليه وسلم): "I am on clear proof from my Lord (Islamic Monotheism), but you deny it (the truth that has come to me from Allah). I have not gotten what you are asking for impatiently (the torment). The decision is only for Allah, He declares the truth, and He is the Best of judges."

(254) Say: "If I had that which you are asking for impatiently (the torment), the matter would have been settled at once between me and you, but Allah knows best the Zalimun (polytheists and wrong-doers)."

(255) And with Him are the keys of the Ghaib (all that is hidden), none knows them but He. And He knows whatever there is in the land and in the sea; not a leaf falls, but he knows it. There is not a grain in the darkness of the earth nor anything fresh or dry, but is written in a Clear Record.

(256) but your people (O Muhammad صلى الله عليه وسلم) have denied it (the Qur'an) though it is the truth. Say: "I am not a Wakil (guardian) over you."

(257) Those who fear Allah, keep their duty to Him and avoid evil are not responsible for them (the disbelievers) in any case, but (their duty) is to remind them, that they may fear Allah (and refrain from mocking at the Qur'an). [The provision of this Verse was abrogated by the Verse 4:140].

(258) And leave alone those who take their religion as play and amusement, and whom the life of this world has deceived. but remind (them) with it (the Qur'an) lest a person be given up to destruction for that which he has earned, when he will find for himself no protector or intercessor besides Allah, and even if he offers every ransom, it will not be accepted from him. Such are they who are given up to destruction because of that which they have earned. For them will be a drink of boiling water and a painful torment because they used to disbelieve.

(259) When the night covered him over with darkness he saw a star. He said: "This is my lord." but when it set, he said: "I like not those that set."

(260) When he saw the moon rising up, he said: "This is my lord." but when it set, he said: "Unless my Lord guides me, I shall surely be among the people who went astray."