Leasons. Things to be taught. Sorcerer's Stone help.
What did the teacher's teach the first years within the first week or two? I know that they learned Wingardium Leviosa in charms, but what about Transfiguartions and the other classes?
The Giant Spider is Hagrid's... Friend?!?
I think they learned how to turn matches into needles in Transfiguration. And Snape definitely cross-examined them on what they already knew. I don't think JKR told us anything about what they learned in DADA all year. History of Magic...well, you can always assume goblin rebellions, but they more likely learned stuff about ancient times.
DADA I think they likely listened to Quirrel stutter about bad things in the Dark Arts