问题补充:
, his mother has to take care of him at home.
A. Being ill
B. His to be ill
C. He is ill
D. He being ill
答案:
A. Being ill
B. His to be ill
C. He is ill
(答案→)D. He being ill
解析:考查独立主格结构:句意:因为他生病了,他妈妈不得不在家照顾他。逗号后面是句子,中间没有连词,说明前面不是句子,而是独立主格结构:逻辑主语+非谓语,因为he和be ill是主动关系,用现在分词being,选D。