问题
选择题
Unbelievable as it is, the film 2012 without doubt________ a warning that human beings are faced with potential dangers
A．belongs to
B．serves as
C．exists in
D．accounts for
答案
答案：B
题目分析：句意为：尽管令人难以置信，但是电影2012无疑给人们了警告，那就是人们将面临潜在的危险。belong to 属于；serve as 担任，充当---的作用；exist in 存在于----；account for--- 对---作出解释。故答案为B。