the mother lowered her head, avoiding eye contact.

[Maybo]

When townspeople walked past, the mother lowered her head, avoiding eye contact.
(The Magic Strings of Frankie Presto by Mitch Albom)

Why is the second comma needed?

 

[5jj]

It marks a natural slight pause in speech.

 

[teechar]

It also sets off the participle clause.

 

[Maybo]

If the second comma is removed, is the sentence still grammatical?

 

[jutfrank]

You need the comma there to set off the participle clause, as teechar has said.

 

[Maybo]

You need the comma there to set off the participle clause, as teechar has said.

Original: the mother lowered her head, while she was avoiding eye contact.
Participle: the mother lowered her head, avoiding eye contact.

Have I understood it correctly?

 

[5jj]

Original: the mother lowered her head, while she was avoiding eye contact.

That is not natural.

 

[Maybo]

That is not natural.

I’m learning participles. I’ve found an explanation from the website:

We can use participle clauses when the participle and the verb in the main clause have the same subject. For example,

Waiting for Ellie, I made some tea.(While I was waiting for Ellie, I made some tea.)

I’d like to know if the sentence from the book matches the above explanation.

 

[jutfrank]

Yes, the mother lowered her head and the mother avoided eye contact.