Question

What is the participial phrase in this sentence "The boy sleeping in the corner is snoring loudly"?

Answer 1

"sleeping in the corner"

Explanation:

A participle phrase is a phrase that starts with a participle (if we're dealing with the present, then it'll be a word normally thought of as a verb and ends with -ing and if we're dealing with the past, then that verb-looking word will generally end`color(white)(0)^color(red)(1)` in -ed) and goes on to describe a noun. It may look like a verb but the whole thing operates as an adjective - it modifies a noun.

http://www.chompchomp.com/terms/participlephrase.htm

In our question, we can rewrite it and eliminate the participle phrase:

The boy is snoring loudly.

Which is fine. But we want to say a little bit more about the boy. Where is he? And what else is he doing, aside from snoring loudly?

The boy sleeping in the corner is snoring loudly.

`color(white)(0)^color(red)(1)` Irregular verbs, as pointed out by @Danial L., will not necessarily end in "-ed". The verb "sleep" for instance has as its past participle "slept" and not "sleeped".