[Grammar] Her arms folded across her chest

[danghuynh88]

Hello teachers !!

"her arms folded across her chest"

This is an example of absolute phrase, but there is a verb "fold" and a subject "her arms" too, so why is it not a independent clause with a passive voice ??

Thanks

 

[danghuynh88]

Thanks Piscean

I thought it was a short term of passive voice when "were" is removed and understood