The origin of the universe is still a sealed book to us.

宇宙的起源对我们来说仍然是不可知的。

youdao

I know a little Russian, but this is a sealed book to me.

我懂一点俄语，但这种语言对我来说如天书一般难懂。

youdao

Books were beyond her interest — knowledge a sealed book.

她对书本不感兴趣，书本知识和她无缘。

youdao

Then they discovered the book in a sealed box and began hailing her for the keenness of her third eye.

CNN: AllPolitics - TIME This Week

In the same way that "people don't buy a book just to read it in the kitchen, " Sealed Media's Peter Kumik says, they like to be able to access the content they have bought on any computer.

BBC: Digital rights and wrongs