Oxford exam taking care of teacher training initially? My word (5,5)
I believe the answer is:
great scott
'my word' is the definition.
(both are expressions of surprise)
'oxford exam taking care of teacher training initially?' is the wordplay.
'oxford exam' becomes 'greats' (nickname for Oxford's 'Literae humaniores' course).
'taking' is a charade indicator (letters next to each other).
'care of' becomes 'co' (c/o can mean 'care of' when addressing mail).
'initially?' suggests taking the first letters (I've seen 'initially' mean this).
The first letters of 'teacher training' is 'tt'.
'greats'+'co'+'tt'='GREAT SCOTT'
(Other definitions for great scott that I've seen before include "Outburst" , "Expression of surprise after Sir Walter?" , "Exclamation of surprise" , "Good heavens!" .)