问题补充：
President Obama has two daughters, able to fit in well with their citizens.
A. both of them are
B. none of them are
C. both of whom are
D. neither of who is
答案：
A. both of them are
B. none of them are
(答案→)C. both of whom are
D. neither of who is
解析：考察定语从句和主谓一致。本题的先行词是two daughters，后面定语从句中whom指代先行词作为of的宾语，因为是两个女儿，故使用both或者neither。句意：奥巴马有两个女儿，她们都可以和别人很好相处。A项不是定语从句，前面可以加上and；B项中的none指三者或者三者以上。D项中的who不能做of的宾语。故C去。
