Wanda VanGoor's explanation of commas and "because" clauses is very
interesting:

> If the "because" clause gives a REASON, no comma is needed.  If the
> "because"clause gives evidence (not reason), use a comma.
>
>       Mrs. VG has gone home because she became ill.
>
>       Mrs. VG has gone home, because her car is not in the parking lot.

Another way of saying the same thing is: If the adverbial clause modifies
just the verb phrase (as in the first example), no comma is needed.  If the
clause modifies the entire main clause, it takes a comma.

Still another way of looking at the second example is to posit an
underlying/understood "I know that" introduction:

        [I know that] Mrs. VG has gone home, because her car is not in the
parking lot.

In this case, the "because" clause is modifying the understood verb "know,"
rather than the spoken verb "has gone home."  That is, in the first example,
she went home because...  In the second, I know it because...

As I said, this is really interesting data.

Dick Veit
UNCW English Department