He is a strict but kind-hearted teacher his students respect but are afraid of .A. one

问题补充：

He is a strict but kind-hearted teacher , his students respect but are afraid of .

A. one whom

B. for whom

C. which

D. that

答案：

(答案→)A. one whom

B. for whom

C. which

D. that

解析：考查定语从句。先行词为a strict but kind-hearted teacher， one做先行词的同位语，同时又是后面定语从句的先行词，后面的从句中his students respect but are afraid of后缺少宾语，所以用whom，故选A。