. I am very grateful to my high school teachers without help I wouldn’t be so excellent.

问题补充：

. I am very grateful to my high school teachers, without help I wouldn’t be so excellent.

A. whom

B. them

C. which

D. whose

答案：

A. whom

B. them

C. which

(答案→)D. whose

解析：考查定语从句，先行词是teachers，定语从句缺少定语，用whose引导定语从句，句意是：我很感激我的高中老师，没有他们的帮助我就不会这么优秀。选D。