Where can I get the subtitles of movies and TV shows

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I like watch English movies and American TV shows.My problem is when I download a latest Movie or a old TV show,I can't find a subtitle in Chinese Sub website.It's really hard for me to understand the dialogs in the movie. Can you recommend me a website where collects intact subtitles which could be download for free? By the way, I don't know how to express the meaning of collect all and without one missing .The word"intact" I used is that right?