0 something positive that could have been achieved, but was not -- 本来可能发生的事（本来有机会达成的好事，但却没有成真）
There's no point now in regretting the might-have-beens. 对于原本可以实现的事情，现在追悔是毫无意义的。
But that is a historical might-have-been and there is no way of proving it.
They obviously must have been a deterrent to some might-have-been applicants for these grants.
But we must abandon the "might-have-been" and face the facts of the present situation.
