Few mathematicians are ------- their futures on finding any such proof; instead, their efforts are focused on finding good, but not -------, solutions for most cases, a field of study aptly known as approximation theory.

A． an outgrowth … pervicacious
B． a visitation … rotten
C． a rejection … vitriolic
D． a permutation … heedless
E． a divagation … rapturous

A． submarine: torpedoes
B． armada: warships
C． exercise: privates
D． ammunition: armory
E． procession: cannonade