As usage

As : reason
As I am suffering from fever.

As I went to my sister's house.

Comparison:
As soft as satin.

As hard as a rock.

As cool as Ice-cream.

Superlative:
As soon as possible (ASAP)

As early as possible

As long as possible

As hot as possible

As short as possible

As clear as possible

As well as: in addition
She is tall as well as pretty.

I like Ice-cream as well as chocolate.

As well: also
I like chocolate as well.

Yesterday I bought some books as well.