My first reading of it was that "were" is the obvious and only correct choice. But then I thought more about it, and it's possible to imagine a situation in which there have already been a group of people who previously have been willingness to work overtime periodically over some period in the past leading up to the present. For example, if yesterday the boss said: I want you to do two things for me.
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Grammar GeekHi, GG. Anything wro
But then I thought more about it, and it's possible to imagine a situation in which there have already been a group of people who previously have been willingness to work overtime periodically over some period in the past leading up to the present.