The aggregate demand function relates any given level of employment to the 'proceeds' which that level of employment is expected to realise.

总需求函数将任何给定的就业水平与该就业水平预期实现的“收益”联系起来。

The value of D at the point of the aggregate demand function, where it is intersected by the aggregate supply function, will be called the effective demand.

总需求函数与总供给函数相交点处的 D 值称为有效需求。

So far we have established the preliminary conclusion that the volume of employment is determined by the point of intersection of the aggregate supply function with the aggregate demand function.

至此，我们初步建立了就业量由总供给函数与总需求函数的交点决定的结论。

But, in the main, it is the part played by the aggregate demand function which has been overlooked; and it is to the aggregate demand function that we shall devote Books III and IV.

但是，总的来说，人们忽视了总需求函数所起的作用；我们将在第三卷和第四卷中讨论总需求函数。