单项选择题 While the causes of the Cretaceous-Tertiary extinction have received the most attention, Alvarez's paper points out work on the other major mass extinctions that may also be ------- for the tragedy.（）

单项选择题 Sadly, Americans of every ethnicity still demand ideological ------- among their own kind--although we're all multiculturalists now, we're much more ...... discussing diversity across the rainbow than within each color.（）

单项选择题 INADVERTENCE:（）