0 indicates a comparison -- så … som …
Take as long as you need to finish it. Ta den tiden du trenger for å bli ferdig.
Are there as many people as last time? Er det like mange folk som forrige gang?
I don’t read as much as I used to. Jeg leser ikke så mye som jeg pleide.
She’s not as pretty as her friend. Hun er ikke så vakker som venninnen sin.
1 indicates to whom or what you are referring -- når det gjelder
2 seeming to show -- som om
4 about a particular subject -- angående
5 indicates the purpose or characteristics -- som