Teacher has the answer-book? (6,3)
I believe the answer is:
master key
'teacher has the answer-book?' is the definition.
I can't tell whether this definition defines the answer.
'teacher has the answer-book?' is the wordplay.
'teacher' becomes 'master' (I've seen this before).
'has' is a charade indicator (letters next to each other).
'the answer book?' becomes 'key' (I've seen this in another clue).
'master'+'key'='MASTER-KEY'
Can you help me to learn more?
(Other definitions for master key that I've seen before include "All-round opener" , "one readily admits!" , "needed for Common Entrance?" , "most useful of the bunch?" , "Locker" .)