9:04 - C-3PO (to Cad Bane): "I don't know what you're talking about." Perhaps coincidentally, Leia also says this (to Vader) in A New Hope [7:56].
9:10 - C-3PO: "I am a protocol droid, human-cyborg relations." He uses the same phrase when he introduces himself to Padmé and to R2-D2 in The Phantom Menace ("I am C-3PO, human-cyborg relations" [39:03 and 39:26]), to Luke in A New Hope ("And I am C-3PO, human-cyborg relations" [20:25]), and to Lando in The Empire Strikes Back ("I am C-3PO, human-cyborg relations" [1:21:31]). He's about to say the same thing in Return of the Jedi, but EV-9D9 interrupts him, so he gets only as far as "I am C-3PO human-cy-" [11:21].
9:41 - C-3PO: "I am fluent in over six million forms of communication." He says almost the same thing in The Empire Strikes Back ("I am fluent in six million forms of communication" [18:38]) and twice in Return of the Jedi ("I am fluent in over six million forms of communication and can readily-" when he's interrupted by EV-9D9 [11:29] and "I am fluent in over six million forms of co-" when he's interrupted by Han Solo [1:11:10]).
14:17 - Cad Bane (to R2-D2, referring to C-3PO): "Your friend Goldenrod turned out to be a huge waste of my time." In The Empire Strikes Back, Han Solo also uses this moniker: "Hurry up, Goldenrod; you're gonna be a permanent resident!" [34:30].
15:24 - Padmé: "Where can 3PO be?" Luke has a similar line in A New Hope as he's trying to raise C-3PO on his comlink: "Where could he be?" [1:22:12 and 1:23:19, the second followed by "3PO!"]. C-3PO himself has a similar line a bit later in A New Hope: "Where could they be?" [1:29:33].
16:13 - C-3PO: "We'll be deactivated for sure." He has two similar lines near the beginning of A New Hope: "We'll be destroyed for sure!" (referring to himself and R2-D2) [2:50] and "You'll be deactivated for sure!" (referring just to R2) [6:39].