I am not quite sure what you mean by "categorize."  Certainly, as the  
subject line indicates, they are subject complements.

I suppose both are locatives:  the "in her car" literally, and the  
"in a bad mood" metaphorically; we often speak of moods as if they  
were places:

She's over the moon.

She's down in the dumps.

She's up for anything.

etc.
On May 13, 2008, at 8:56 PM, Peter Adams wrote:

> How would you categorize the prep phrase, "in a bad mood," in a  
> sentence like the following?
>
> Cornelia was in a bad mood.
>
> How about the prep phrase "in her car" in the following sentence?
>
> Deb was in her car.
>
>
>
> Peter Adams
>
> To join or leave this LISTSERV list, please visit the list's web  
> interface at:
>     http://listserv.muohio.edu/archives/ateg.html
> and select "Join or leave the list"
>
> Visit ATEG's web site at http://ateg.org/

To join or leave this LISTSERV list, please visit the list's web interface at:
     http://listserv.muohio.edu/archives/ateg.html
and select "Join or leave the list"

Visit ATEG's web site at http://ateg.org/