Discerning between man and zone coverage

Question
Hi, I have a question as a fan trying to expand his knowledge of the game. When watching TV broadcasts of games, I've been having trouble understanding when cornerbacks are playing man or zone, and when I do know I then have trouble figuring out where their zone is located and how it fits into the coverage shell as a whole. I understand the basic concepts of zone defense, like if a team is in cover 2 it means there's two deep guys and the underneath area is split into zones for the remaining players in coverage - if it's a 4-man rush, that means the underneath area is split into five sections, flat zone, curl zone, etc. But when I see it all in action it just becomes a confusing mess for me, especially with NFL games where defenses show conventional looks pre-snap and then roll into all kinds of crazy coverage shells after the snap. I have the same problem with linebackers and their underneath zones too, like if a TE runs a pass pattern and the strong-side LB (aligned over or near him) covers him, is that man or zone? And are there any things I can look out for that tip off what kind of shell the coverage is rolling into after the snap?

Thank you for your time!

Answer
 The best way to answer your question is if the linebacker you are referring to runs deep down the field with the tight end.  If he does he is not in zone he is in man.  The basic 4-3 package is that the outside lb's have the flats from about the line of scrimmage to about 7 yards.  The corners have from the line to about 18 yards down field.  The two safeties have the deep halves.  And last but not leeast the middle backer drops back and covers the middle of the field and trys to read the qb eyes and get into the passing lanes.
 The NFl has all kinds of coverage schemes, and zone blitzes along with man mixed with zone, so it hard to explain all of them at one time.  COach NOEL!