Add comments to (8)
I believe the answer is:
annotate
'add comments to' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for annotate that I've seen before include "Provide interlinear or marginal comments in a book" , "Add explanations and comments to (a text)" , "Supply explanatory notes" , "Make notes upon" , "Write down comments on" .)