Hmmmmm. Interesting. I talk about "going to see a movie" but when I am in the theater I watch it. So, yeah, watch does seem more passive. Adults still use "flicks" here in New England but it makes the teens roll thier eyes!
Previews because they are teasers for future showings. Also sometimes billed on the screen as "Coming Attractions."
I remember the "trailers" that came on between the double feature at the local cinemas... For 10 cents (children) or $25 cents (adult), you got a newsreel, several cartoons and two movies - a "B" film and the main feature.
First time I saw a movie with just a newsreel and a main feature was at the Strand Theater in Lowell, Mass, the noon showing of "Gone With The Wind." It was 25 cents for children (no candy for Ann) and four hours long. I skipped school to see the show and got home an hour and a half late from "school" (ahem) and caught hell from the parents.