1. What does the following statement mean?
"You've been served."

2. Normally, we use a singular noun as an adjective. For
example, a teacher transfer or a job vacancy.
When do we use a plural noun as an adjective, such as,
a teachers college or a jobs cut?
And when do we provide an 's to the plural noun used as
an adjective: a women's magazine?

Thanks for your explanation.