What are the episodes that have the average rating with more than 20 of 2-star votes?
2-star refers to stars = 2; average rating refers to 5 < rating < = 7; more than 20 of 2-star votes refers to votes > 20
SELECT DISTINCT T1.episode_id FROM Episode AS T1 INNER JOIN Vote AS T2 ON T2.episode_id = T1.episode_id WHERE T2.stars = 2 AND T2.votes > 20 AND T1.rating > 5.0 AND T1.rating <= 7.0;