Answer:
Simile
Explanation:
This is a simile. A great way to identify a simile is to look for the words "like" or "as".
"A constant whirring that had a metallic ring every few seconds, like sharp knives rubbing against each other."
A simile compares two things. In this sentence, the "constant whirring" is being compared to "sharp knives".
I hope this helps :)
