She couldn‘t take shorthand, _______ slowed down the work of th

She couldn‘t take shorthand, _______ slowed down the work of the office.
A、that
B、which
C、it
D、so
【正确答案】:B
【题目解析】:take shorthand 速记。后半句缺少主语,排除D,逗号不能连接两个独立的句子,排除C,判断此处为定语从句,that不能引导有逗号 的非限制性定语从句,which可以,因此选择B