问题补充：
Some students are afraid of the teachers strict with students.
A. that is
B. which is
C. who are
D. who is
答案：
A. that is
B. which is
(答案→)C. who are
D. who is
解析：句意：一些学生害怕对学生要求严格的老师。本题考查的是定语从句。题干中who are strict with students 是一个定语从句，先行词为teachers，是人，且是复数，故选C。
