We were required not to any important details before it was made public.
A. try out
B. make out
C. let out
D. break out
网友回答
A. try out
B. make out
(答案→)C. let out
D. break out
解析：考察动词短语辨析。A尝试；B辨认出，理解；C发出，泄露；D（战争，火灾）爆发；句意：我们被要求在公布之前，不要泄露任何重要的细节内容。根据语义说明C项正确。