Studying English commercial, interrupting call (7)
I believe the answer is:
reading
'studying' is the definition.
('read' can be a synonym of 'study')
'english commercial interrupting call' is the wordplay.
'english' becomes 'E' (abbreviation).
'commercial' becomes 'ad' (abbreviation for advertisement).
'interrupting' indicates putting letters inside.
'call' becomes 'ring' (telephone call).
'e'+'ad'='ead'
'ead' inserted inside 'ring' is 'READING'.
(Other definitions for reading that I've seen before include "Where Oscar Wilde penned" , "Perusing; university in Berkshire" , "university town" , "Quiet activity" , "Interpreting text" .)