We must take two aspects into consideration, both of associated with the safety of the students .
A. which
B. whom
C. that
D. them
网友回答
A. which
B. whom
C. that
(答案→)D. them
解析：
试题分析:句意：我们必须把这两方面考虑进去，这两方面都关系到学生们的安全。分析结构可知逗号后面没有谓语动词，但是意思完整，应该是独立主格形式，即：名词/代词+现在分词/过去分词/形容词/名词等，故答案选D。