Sheldon were told that there is going to be a welcome party for Dennis who's agreed to join them in university.
Sheldon seemed a bit jealous that he was going to be replaced by a 15-year-old after a long time he'd been thinking he was the smartest guy in the world.
spread: if you spread something somewhere, you make it everywhere covering a large area which people can see it easily.
obvious: when something is obvious, it is easy to see and understand.
oracle: in ancient times, a oracle is a priest who make predictions about future events.
matrix: the things happen in the future or things eventually develops
agree: if two people agree with something, they have the same opinion about it.
