as / as ; so/ as

Witam. Kiedy stosujemy as ....as , a kiedy może to być so ... as

Ponawiam pytyanie .
przykładowe zdania:
John doesn't speak English (as so) badly as he speaks French.
She doesn't work (so as) well as her sister.
I don't walk (as so) fast as you.
We came ( as so ) quickly as we could. (tylko as jest poprawne)
Proszę o pomoc bo nie ogarniam tego.

as przymiotnik as przymiotnik - zdania tw, przecz
so przymiotnik as przymiotnik - tylko przeczenia

She isn't so/as clever as me
She is so clever as me.
She is as clever as me.

Uzupelnijac powyższy post kolegi :
Z niektórymi przymiotnikami w takich negatywnych konstrukcjach porownawczych zamiana pierwszego ‘as’ na ‘so’ jednak moze byc nie do przyjecia bo nie zachowuje to tego samego sensu wypowiedzi co z dwoma ‘as’:
Their baby is not as old as she thought.
?Their baby is not so old as she thought. ( takie zdanie w domysle moze sugerowac ze dzieciak 'was already somewhat old ')

Dziękuję, teraz już jest to jasne.