问题详情：
My father is getting old. He needs a stick _______ to walk.
A. in which B. by which
C. with which D. with whom
【回答】
解析：选C。句意：我父亲一天天变老了，他需要一个拐杖来辅助他走路。a stick后接一个with which to walk的定语，相当于with which he can walk这个定语从句。with. . . “用……”。而其他介词不符合题意。
知识点：定语从句
题型：选择题
