Study and try hard when they force one to (9)
I believe the answer is:
constrain
'they force one to' is the definition.
The definition suggests an adverb but the answer is not.
'study and try hard' is the wordplay.
'study' becomes 'con' (con can informally mean to study).
'and' says to put letters next to each other.
'try hard' becomes 'strain' (I've seen this in another clue).
'con'+'strain'='CONSTRAIN'
'when' is the link.
Can you help me to learn more?
(Other definitions for constrain that I've seen before include "Compel; constrict" , "Restrict the extent of" , "Compel towards a course of action" , "Force" , "Restrict scope of (an activity)" .)