Dear teachers,
Would you be kind enough to explain to me the authoritative grammatical rule concerning the expression in bold in the following excerpt from an English text?
“Measures of another kind that can also be employed by the Secretary Council are the operations of the UN peace-keeping armed forces and military observer missions.
There is a plural in my native language also by the substantive “military obsevers”.
Thank you for your efforts.
Regards,
V.

