closed
英 [kl??zd]
美[klozd]
- adj. 关着的；不公开的
- v. 关；结束；接近（close的过去分词）
词组搭配
behind closed doors
taking place secretly or without public knowledge
秘密地；暗中地
closed book
a subject or person about which one knows nothing
完全理解不了的科目；完全理解不了的人
accounting has always been &B{a closed book to} me.
会计学对我来说一直是一门完全理解不了的科目。