It was long supposed that the main difference between animals an

It was long supposed that the main difference between animals and plants was that the former could move about while the ________could not.
A、other
B、latter
C、another
D、later
【正确答案】：B
【题目解析】：本题考查固定词组。the former…the latter..表示“前者…后者…”的意思。句中it做形式主语，真正的主语是the main difference between …could not.句意为：一直以来，人们认为动物和植物之间最大的不同就是前者可以走动而后者不能。