57.The author deepened his understanding of the power of CRM when_______.
(A) he saved the plane by speaking up 　
(B) he was in charge of a flying task 　
(C) his boss landed the plane too late 　
(D) his boss operated on a patient

细节理解题。根据第二段最后一句可知，作者在经历了一次飞行给上级提出了意见之后，对CRM有了更深的理解，故选A。