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.

A． van: sedan
B． nebula: star
C． missile: dart
D． toe: foot
E． item: catalogue

A． banal: repartee
B． selfish: ego
C． comely: hatred
D． fiendish: impatience
E． retentive: memory