问题详情

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．betting… perfect
B．developing … convenient
C．pinning … substandard
D．destroying … exact
E．establishing … vague请帮忙给出正确答案和分析，谢谢！