单项选择题
A．An area of a country smaller than the nation considers itself to be a nation.
B．A boundary is demarcated around a nation which does not include the people of the nation.
C．A continent is divided into two areas for implicit ideological purposes.
D．Two nations dispute the exact geography of a border based on an ancient historical claim.
E．The history of a nation is erroneously conflated with the character of one particular region.
单项选择题 Which of the following most accurately describes the passage（）
单项选择题 According to the passage, behavioral psychologists studying the extinction process have discerned which of the following（）
单项选择题 According to the passage, "infralimbic neurons … fire to the tone only when rats are recalling extinction on the following day" for which of the following reasons（）