题目内容：

I saw my mother ___upstairs just now.A go B went C does D to go

优质解答

选B.
译文：我看见,我的妈妈刚才下楼了.
my mother went upstairs just now 是看见(saw)的内容,作宾语,是宾语从句.
主句用过去时,从句也用过去时.