by JonathanSchneider Sat Jun 06, 2009 7:18 pm
Actually, neither sentence carries the right meaning, exactly. You're looking for this:
"Seeing movies in theaters remains a passion of most teenagers, even though they can watch the movies on DVD at home."
We prefer "even though" to "even if" in this case because we mean to express that the teenagers actually CAN watch the movies at home. "Even if" would suggest that it is unknown whether the teenagers can watch movies at home.
The "can" vs. "could" split is a bit different. In one sense, "can" vs. "could" is the split between present and past tense. As we mean to suggest that the teenagers have this option in the present, we would use "can." However, we could use the word "could" (the simple past) as the hypothetical subjunctive. This would make sense after the "if," but only if we meant to imply that teenagers either certainly or most likely CANNOT watch DVDs at home. These issues are discussed in more depth on pages 134-135 of our third edition guidebooks, and pages 112-113 of the fourth edition.