The person in __charge of the program was at __complete loss when the incident happened.
问题描述：
The person in __charge of the program was at __complete loss when the incident happened.
A./;/ B./;a C.the;/ D.the;a
答
in charge of,固定短语,表示“掌控、支配、掌管”.注意与in the charge of（受……的支配）区别.
at a loss,也是一个固定用法,表示茫然不知所措、不知如何是好.另外这个词组还有“（经营）亏本地,赔钱地”意思.