Watch and study and learn. Well, that explained how the Doctor knew so much. But no traveling? "I guess you're not supposed to interfere, either," he said, chuckling. Talk about interfering! In a good way, though. The Doctor had saved so many lives, so many worlds. Countless times, she had saved the Earth as well.
Steve frowned at Susan. "What do you mean, save you? What was happening at the Academy?"
Then he paused. "You can ask me questions as well, if you like. I'm supposed to be showing you around."
Natasha appeared, from a side corridor. "Steve, did you know your friend speaks fluent Latin? And he-- oh. Hello." She gave Susan a smile, then Steve a look that clearly asked, We're bringing kids in here now?