Took in bits of a course writer ran (7)
I believe the answer is:
nibbled
'took in bits of a course' is the definition.
'writer ran' is the wordplay.
'writer' becomes 'nib' (something which writes).
'ran' becomes 'bled' ('bleed' can be a synonym of 'run').
'nib'+'bled'='NIBBLED'
(Other definitions for nibbled that I've seen before include "Took small bites (of something)" , "Gnawed" , "Took small bites; ate intermittently" , "Ate sparingly" , "Bit off very small pieces" .)