单项选择题 With a smirk, the（）historian takes it as a professional obligation to parade human nature always as an object of（）

单项选择题 Science and society are（）collaborators: In the best of worlds we may achieve a very fine and finely negotiated partnership, and in the worst of worlds,（）one by the other.

单项选择题 In view of the fact that his enemies knew him as cheerful, his allies exhorted him, as a matter of self-preservation, to（）himself as taciturn.