with blues, i know what the chords are underneath the soloing, i can recognize when they are playing over the IV or the V or the I. so i know the context in which i can use the licks and what part of the progression they sound the best in. but for jazz. i can't recognize any of the changes so when i learn a line from someone, i don't know if he played it over a ii-V-I progression, or over a ii-V, or over some other chord. as a result, i end up just knowing the line, but not how to use it in context. even when i have the lead sheet of the tune in front of me, with the progression, jazz players like to alter the progression and chords so much, that in the end i'm not really sure what is going on underneath the soloist. what did you jazz guys do in order to fix this problem?