Frank Spriggs was a very able man but something of a closed book.

弗兰克· 斯普里格斯是个非常能干的人，却不被人所知晓。

Fishing is a closed book to me.

我对钓鱼是一窍不通。

Philosophy is a closed book to me.

我对哲学一窍不通。

Nuclear physics is a closed book to me.

核物理学是我完全不懂的一门学科。

A closed book.

一本合上的书。