问题补充：
What we all know is that the old scientist, life was hard in the past, still works very hard in his eighties.
A. for whom
B. for him
C. for whose
D. for which
答案：
(答案→)A. for whom
B. for him
C. for whose
D. for which
解析：这是定语从句，因为that引导的是表语从句，the old scientist still works very hard in his eighties.是主句，life was hard in the past是定语从句，两个句子中间缺少关系词，him不能起连接的作用，故排除B；先行词是the old scientist，which不能代替人，故排除D；如果用for whose，那么从句中就缺少主语，因为for whose life是介词短语不能作主语，这里选for whom，life是从句的主语，故选A。
