The old lady is said to have three children two of studying abroad.A. whomB. themC. allD.

问题补充：

The old lady is said to have three children，two of studying abroad.

A. whom

B. them

C. all

D. who

答案：

A. whom

(答案→)B. them

C. all

D. who

解析：句意：老太太说,有三个孩子,其中两个在国外学习。逗号把句子隔开，前后又没有连词，逗号前的句子是主句，逗号的句子是定语从句，them 和all无法引导定语从句，故排除。放在介词of之后要用关系代词 whom。故选B。