I'm often confused between this two terms participle clause and participle phrase used in English grammar.I've read through some websites about them but got further confused.To be honest,I don't understand some other English grammatica terms such as adverbial clause,verbals etc even after reading through many websites.However,Now,As I'm learning about participle,I want to understand these terms.Do the following sentences contain participle clause:
1.Entering the room, he caught us sleeping.
2.Opening the envelope, I found two concert tickets.
If they don't contain participle clause why these http://www.grammarbank.com/participle-clauses.html http://www.grammaring.com/participle-clauses websites are describing them as participle clause?
could you please make me understand about both participle clause and participle phrase?