something i dont understand about the oscars...

[Javier]

It really depends on the type of film you're doing, the type of lines you have, and there are just so many different factors that can be involved in the film.  Some actors have long ass monologues that of course you have to remember.  Or long ass scenes as well.  Other time, you really have the freedom to work around the script but this is less likely and mostly found in comedy type movies.  I'd still say most actors have to memorize a lot.  The hardest part is actually acting and becoming a character, which is art and one of the best thing about films or tv. 

[Blasphemy]

Actors do not remember lines, they read the script, and have it on hand.

man you realize how stupid that sounds right? have you ever seen a movie where an actor is reading off a script? they might remember it dy by day for the scenes theyre shooting but they have to remember it

You also have to remember, sometimes Actors will Adlib lines in films. Depends on the Actor, hell Brando had been using Cue cards for some films, so in the end Not all of them remember there lines or even need to.