The popular sitcom "The Big Bang Theory" on the American CBS channel welcomes its fourth season. The story not only revolves around four lovely physics geniuses, Leonard, Sheldon, Howard and Raj, and the blonde beauty next door, Penny, but also adds new characters. What new surprises will these characters bring to the fans? After Leonard (Johnny Galecki) and Penny (Kaley Cuoco) broke up, they decided to continue to be ordinary friends. At the same time, after several months of text communication, Sheldon finally decided to date neurobiologist Amy, which was his first date in his life. Will Amy, who is a perfect match for him, become his girlfriend in the end? Penny is very interested in "Shami Love", but finds herself an awkward light bulb. In this season, Howard's girlfriend Bernadette will also return, and his good friend Raj is still at the stage where he can't communicate normally with women.