"Because," the second Superman explained patiently, "You weren't actually shot, thanks to your future self - me - coming back in time and saving you. See?"
Clark thought very hard about this. Time travel always made his head hurt, though so he soon gave up the effort.
Time travel would make anyone's head hurt. Especially the amount that Lois and Clark seem to do between Alt Universes and Future, Past jumping they've done.
"Twenty," the other Superman responded automatically, then quickly added, "hundred."
"Twenty hundred?" Clark echoed. "Do you mean two thousand?"
"Yes," said Superman. "That's, uh, how people talk in the future."
"Twenty hundred years from now?" Clark asked, raising an eyebrow.
Talk about a giant leap in time.

"So why--"
"Man, you ask a lot of questions!" Superman interrupted, rubbing the bridge of his nose. "You're even worse than my kid sister!"
Clark paused. "Kid sister?" he echoed.
Now THAT is confusing...
Superman looked up. "What?"
"You just said you had a kid sister," Clark pointed out. "I never had any brothers or sisters."
Superman suddenly had a faraway look on his face. "Neither did I," he said, sounding a bit awed, "but, suddenly, I'm starting to remember some!" He turned back to Clark, looking very alarmed. "It must be because I changed the timeline!" he said.
Yes, that explains everything....Not really.
"Now, hold on a minute!" said Clark. "First of all, you were trying to tell me that this was just a time loop; second of all, how would me saving my own life in the past have anything to do with me suddenly having brothers or sisters?!"
Superman started to sweat a little. "Well, there's actually a very simple explanation," he said. "You see...hey, what's that?"

He just got Superman'd Now he knows how Lois feels when he runs out in the middle of a conversation...
But right now, he was headed for home: his dear wife had something important to tell him, and he didn't want to be late.
Awwww.... I'm going to take a wild guess here and guess the 'important thing' is that she's pregnant.

Very nice. Thanks for the fun read Queen of Capes!
