I don't know

I don't know

The finger's shape is secret and unknown. It's the same as "God doesn't know, ghost doesn't know".

Idiom explanation

[explanation] the finger is secret and unknown. It's the same as "God doesn't know, ghost doesn't know".

Idioms and allusions

[source]: Zhang Yi's work in the enemy area: "besides, we came in without knowing it."

Discrimination of words

It can be used as an adverbial or a clause to describe a secret thing