Said it had been assessed by the teacher again
I believe the answer is:
remarked
'said' is the definition.
(remarking is a kind of saying)
'assessed by the teacher again' is the wordplay.
'assessed' becomes 'marked' (marking is a kind of assessing).
'by' says to put letters next to each other.
'the teacher again' becomes 're' (I can't justify this - if you can you should believe this answer much more).
'marked' put after 're' is 'REMARKED'.
'it had been' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for remarked that I've seen before include "Commented - noticed" , "Comment made about deer mark" , "Commented, made observation" , "Made comment or observation" , "Observed, pointed out" .)