My mother, （）whether anyone would come home to help her, had to prepare the supper all by herself.
A、
did not know
B、
not knowing
C、
had not known
D、
having not known
【正确答案】：B
【题目解析】：
本题考查的是现在分词作状语。句子已有谓语，即had to，排除A和C。分词的否定形式为在分词前加not，即not knowing。
句意：我母亲不知道是否有人会回家帮助她，只好自己准备晚饭。