when to leave, I could only stay at home, nothing.
A. Knowing not; done
B. Not knowing; doing
C. Having not known; done
D. Not having known; doing
网友回答
A. Knowing not; done
(答案→)B. Not knowing; doing
C. Having not known; done
D. Not having known; doing
解析：考查非谓语动词，第一空，分词的否定式，not应放在分词的前面，可排除A和C，没有明显的先后顺序，不用分词的完成式，第二空，doing作伴随状语。所以选B。