If you're going to show a classic film to Chinese friends and/or students that more or less proves how great American films can be, may I recommend to you four simple words:
Back. To. The. Future.
... (ahem, cough) parts I, II, and III.
Really, these films are fantastic. Doc Brown has gotta be one of the best movie scientists ever, Marty McFly is a great runt of a hero, Biff is such an aggressively bad bad guy, and the DeLorean and flux capacitor and 1.21. gigwatts ("jigawatts") are still great, and then there's comedy and special effects and romantic sub-plots and skateboard/hoverboard/horse chases and time travel in-jokes ... it's got it all! The films hold up amazingly well even today (well, Part II seems a little dated since it shows a 2015 with no internet or mobile phones), and aside from a lot of "holy shit"-level swearing (but remember, any time someone learns a foreign language, they always memorize the curse words first), there's nothing to really bat an eye over. Sure, I could show Pulp Fiction or The Godfather (part one, you swine!) or The Shawshank Redemption, but they all deal with gangsters and murder and sodomy.
Back to the Future just plain rocks.