After being puzzled for some unknown reason after watching Superman II, i decided to watch it again and this time realized what it was that was puzzling me.
There is a scene where Lois Lane believes Clark Kent is superman and to prove the point, she points a gun loaded with blanks at Clark and fires. Clark flinches and then admits he is superman, just before Lois tells him there were blanks in the gun. . .
Well, if Clark was indeed Superman, wouldn't he have realized through his superpowers of x-ray vision and superhuman perception that no bullet came out of the gun ? ? ?
In the original cut of "Superman II," in order to trick Clark into revealing he is Superman, she jumps into the river at Niagara Falls. He uses super-breath to push a floating log near her in the river, then jumps in (as Clark) and helps pull her out. Later that night in the romantic hotel suite, Clark trips and his hand falls into a blazing fireplace and Lois figures out he is indeed Supes.
In the "Richard Donner Cut" (the re-edited version of Supes II which was released in 2006), first, Lois jumps out the window at the Daily Planet in an attempt to sucker Clark into giving himself away. He uses super-breath to push her into landing on a canvas canopy and then on a pile of fruit and vegetables, so instead of getting killed or revealing Clark's secret identity, she ends up splattered with tomatoes.
Later in the "Donner Cut" she pulls the loaded-gun trick, and you are correct: Clark would certainly have known if the gun was loaded or not, used x-ray vision to see if it was loaded, his super-hearing would have heard the hammer connect with the shell, and of course he would have caught/melted the bullet coming out of the chamber as it was fired.
In both cases he reveals to her that he is indeed Superman, but then before the end of the movie he decides to brainwash her with super-hypnotism and make her forget she ever knew the secret (bringing the question up once again: how stupid does Lois Lane -- supposedly an award-winning journalist -- have to be, to swoon endlessly over Superman, and yet never figure out that he's the guy who sits two desks across from her at work?).
The Superman/Lois Lane relationship is very, very strange. They both take turns acting like complete morons, and treating the other with utter contempt.