What did Macbeth ask or say when he is told his prophecy?

When Macbeth hears the prophecy, he doesn't believe it. The witches greet him as "thane of Glamis," which is his current title, but also as "thane of Cawdor," a title belonging to a man Macbeth believes to be still living. Becoming king, he adds, "stands not within the prospect of belief." He is obviously genuinely taken aback, as his companion Banquo asks him why he seems "to fear things that do sound so fair." Of course, Banquo himself is the subject of a prophecy. Macbeth demands that the witches explain themselves, and how they came by such knowledge. Later in the scene, as the witches depart, he learns that one part of the prophecy has come true. The thane of Cawdor is about to be executed for his role in a rebellion against Duncan and Macbeth will be the new thane of Cawdor. This causes him to think the next part of the witches' prophecy might be true, and that he might become king. When the scene closes, he has gone from dismissing the witches as tricksters to admitting that "if chance will have me king, why chance may crown me without my stir." So Macbeth's spoken responses run from incredulity to astonishment to anticipation of what the future might hold.