We_finished our assignment when the teacher came to th door A had just had B have just had选哪个?

问题描述:

We_finished our assignment when the teacher came to th door A had just had B have just had选哪个?

A.过去完成时
从句里when teacher came用了一般过去
而我们完成作业是在这之前,所以要推一个时态.