问题补充:
The school has developed an online systemstudents can choose their own teachers.
A. which
B. that
C. whom
D. where
答案:
A. which
B. that
C. whom
(答案→)D. where
解析:考查定语从句:句意:学校已经开发了一个在线系统,里面学生可以选择自己的老师。这是定语从句,先行词是an online system,定语从句中缺少的是地点状语,选D。