Thanks a lot for your quick response – your help actually came just in time, and I sent ‘each type of document’.
Use of the singular form is unnatural to me, as in Russian we would use each type of document, each type of animal only if we previously typified a specific document or species.
And we always use the plural form when there are different documents or we consider various animals - dogs, rabbits, foxes, etc - altogether.
Each type of documents, each type of animals… or types of documents…
But I understand the point, thank you. That’s English…
The only thing that is a bit unresolved is with type of things. I suppose, it might be a special case.
Some examples from BNC:
If we attempt to put the wrong type of things together, or attempt separate explanations of things which are part of the same natural kind, then we are going to struggle to produce successful science.
You ought to save them wooden type of things for it.
sara.natcorp.ox.ac.uk/cgi-bin/sa … +of+things
But as I have never actually needed to use that ‘type of thing(s)’ and my question was quite pragmatic – that’s enough for me, for the moment.
P.S. About the article with moderator - my particular case related to the team of inspectors that had (has) the only moderator/coordinator position/role.
But, of course, the role itself is not unique.
So - (be) trained as a moderator, OK.