___,Mary had to stay at home to look after her.A.Her mother was ill B.Her mother being ill 注：要具体解析
问题描述：
___,Mary had to stay at home to look after her.
A.Her mother was ill B.Her mother being ill
注：要具体解析
答
B，
因为一个句子只能存在一个动词。
主句里有动词had to
A里有BE动词was
B里只有现在分词，没有动词
所以选B
答
B
A是一个完成的句子 后面的成分也是 两个完整的句子之间要用连词联起来 如果mary前面加个and就可以选A
B是一个独立结构 用了非谓语动词being,所以无需用连词