I couldn't hear the difference between zu and so in your audio file...
I agree. The speaker says "zu". Please report it. [Native German speaker]
I confirm. I asked a German native speaker (without showing the answer) who also heard "zu" instead of "so".
Ich höre "zu" auch.
Five years have passed, seems like the problem remains...
I agree too
Why "very big" is incorrect here?
Because 'so' does not mean 'very'.
Is "My house is not very big" really wrong?
On the slower version of the sentence the pronunciation is clear to understand.
"so" is here working as demonstrative pronoun? why does not use "das"?
No, it's an adverb. It modifies "groß".
I never heard the 'so'..... sigh.....
The translation is wrong