1: "The Big Bang Theory returns with a new spinoff series."

2: "Fans still debate 5 Big Bang Theory relationships."

3: "Leonard and Penny's on-again, off-again romance."

4: "Sheldon and Amy's quirky yet lovable bond."

5: "Raj and Howard's iconic bromance."

6: "Bernadette and Howard's unexpected love story."

7: "Penny and Sheldon's unlikely friendship."

8: "The Big Bang Theory's enduring appeal."

9: "Join the debate on these iconic relationships."