Question

He is not aware _ his mistake

Answer 1

The answer to this question is 'of'.

He is not aware of his mistake. 'of' is the pronoun that fits well in this blank.

Other pronouns 'from' will not fit here.

However, if the sentence was learning __ mistakes, then the pronoun 'from' would have fit well.

Hence, the word of will suit here in the blank.

Answer 2

$\color{blue}\huge\underline {\:HEY\:MATE}$

Here is your answer..

He is not aware $\color{black}\underline \mathcal{\:OF}$ his mistake.

Here only this pronoun fits well with this sentence. It cannot be substituted using another pronoun.

Hope it helps you.
#Platz ✌️