Then tell me, Future Boy, who's President in the United States i...
[Dr. Emmett Brown is doubting Marty McFly's story about that he is from the future]
Dr. Emmett Brown: Then tell me, "Future Boy", who's President in the United States in 1985?
Marty McFly: Ronald Reagan.
Dr. Emmett Brown: Ronald Reagan? The actor?
[chuckles in disbelief]
Dr. Emmett Brown: Then who's VICE-President? Jerry Lewis?
[rushing out and down a hill toward his laboratory]
Dr. Emmett Brown: I suppose Jane Wyman is the First Lady!
Marty McFly: [following Doc] Whoa! Wait! Doc!
Dr. Emmett Brown: And Jack Benny is Secretary of the Treasury.
Marty McFly: [outside the lab door] Doc, you gotta listen to me.
Dr. Emmett Brown: [opens the door to the lab] I've had enough practical jokes for one evening. Good night, Future Boy!
[closes the door leaving Marty outside]
Marty McFly: No, wait! Doc. Doc. The-the-the bruise - the bruise on your head. I know how that happened! You told me the whole story. You were standing on your toilet, and you were hanging a clock, and you fell, and you hit your head on the sink. And that's when you came up with the idea for the Flux Capacitor...
Marty McFly: Which... is what makes time travel possible.
[Doc opens the door and looks at Marty with a stunned look on his face]