A third episode focused on the Ponds, I know maybe I'm becoming stale, but whatever you might think of the Ponds themselves, there's no denying that the part they played in the show was written as one of the most emotion driven, and was really intended to pull at the heart strings. It's this then, that makes the next time trailers for the episodes focussing on them particularly good, because there's always a little hint at something bigger with them, namely how their lives and relationship is/has been effected by the presence in their lives of The Doctor. What really makes this trailer a good one is that it teases a genuinley interesting premise. 'A faster time stream', and even though the specifics aren't in the trailer, we know that somehow this will present Rory with a situation in which he has to choose between two Amy's, and just to add a little intrigue to things, one of them is visibly older than the Amy we're used to.