closed book meaning in English
未知之事，不可理解的事情。
Examples
- The man's early life is a closed book .
那人的早年生活是个不可告人的谜。 - Nuclear physics is a closed book to most of us .
我们大多数人对原子核物理学一窍不通。 - For me , geology is a closed book
对我来说地质学是一门我完全不懂的学科。 - Nuclear physics is a closed book to me
核物理学是我完全不懂的一门学科。 - Paper i : choose 2 questions and answer in 3 hours . closed book
卷一：以三小时选答两条题目(闭卷)