If you attend it, a present will be expected from you (4,4)
I believe the answer is:
roll call
'you' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'if you attend it a present will be expected from' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'will' could be 'll' (contracted form, as in 'he'll' - 'he will') and 'll' is found within the answer.
'from' could be 'o' (I've seen this in other clues) and 'o' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for roll call that I've seen before include "List of names read out" , "Means of checking attendance" , "Method of checking who's present" , "Calling out of list of names" , "Means of establishing who is present" .)