is known to us all is that the old scientist, for life was hard in the past,still works very hard in his eighties.
A. As; whom
B. What; whom
C. It; whose
D. As; whose
网友回答
A. As; whom
(答案→)B. What; whom
C. It; whose
D. As; whose
解析：本题考查连接代词。 is known to us all 是主语从句，排除AD,第一个空上的词要做主语，第二个空上的词做for的宾语，代替the old scientist。
【标签】复合句