Yes, we usually start watching American TV plays to improve our English, but later we will find that our attention is focused on the plot, not the subtitles below. Actually, it's good to watch American TV series and practice listening, but it doesn't matter what level watching American TV series can improve our English. If you choose a suitable movie, such as The Shawshank Redemption, you can find it online yourself, such as AISI English website. At least it's better than sitting there reciting words. In the process of watching movies, we can cultivate our sense of language and learn some good vocabulary. The important thing is that we enjoy the process!