posted by Henry2 .
I included the sentences I was most doubtful about. Thank you.
1) In each episode there was a flashback, which showed what the characters were doing before the crash. Through the flashbacks (?) the audience learned more about the characters (could learn more about the characters).
2) A really interesting character was the American doctor Jack interpreted (played) by Matthew Fox.
3) The island, however, kept its mystery till the series ended in 2010.
4) What was on Channel five last night?
What did you watch on TV last night?
Was there anything interesting on TV last night? I watched Lost but after a quarter of an hour I fell asleep.
5) Did you see (or watch since it is on TV) the last episode of "Lost"?
When is the next episode of Lost? (can you say that?)
All looks good, including the alternatives in the last one. Add commas and delete things in parentheses in the earlier sentences.