be not to know
成語所屬單字know
be not to know — 慣用語
1. Used to say that someone had no way of realizing they did something wrong.
1.慣用語
釋義
無從得知
Used to say that someone had no way of realizing they did something wrong.
例句
Don't blame him for the mistake; he was not to know.
I'm sorry I broke the vase. You weren't to know it was fragile.