There's Neville, eating as usual.

[Xonela]

We sometimes use a comma before a participle clause:

> There's Neville, eating as usual.
> In came the first runner, closely followed by the second.
> A little girl walked past, her doll dragging behind her on the pavement.
> The bomb exploded, destroying the building

And sometimes not:
> We can offer you a job cleaning cars.
> I found him sitting at a table covered with papers.

How does it work?

 

[Tarheel]

We can offer you a job. What kind of a job? A job cleaning cars.

Context counts!

 

[Tarheel]

Didn't your source provide an explanation?

 

[Tarheel]

I found him sitting at a table covered with papers.

Where would you insert a comma, and why?