my mother told us that we would not be--christmas gifts beca

My mother told us that we would not be＿＿christmas gifts because there was not enough money.
答案选：B
be receiving 不是表被动,被动语态是be done的形式,有些词后面加doing确实表被动,但不包括be动词.如：worth doing 值得被...
这里其实是用进行时表将来的,比如《走遍美国》书上有这么一句：
What are you doing tomorrow?
i will be meeting you at the airport.
你这句话中,主句用了过去式：told us,所以相应的从句变成了would be doing 而不是 will be doing
翻译：母亲告诉我们,我们不会收到圣诞礼物,因为钱不够.
because后面决定了不能选A.
再问： 老师说这是虚拟语气，would be doing 约=would do ？？帮忙解释一下