Answer:
1. Sudden break in thought
2.Introductory interjection
3.Introductory adverbial clause
4.Appositive
5.Parenthetical expression
Explanation:
1. My mother—what a pianist—taught me all I know about music.
a sudden break in thought
2. Yes, I feel that water color is an exciting hobby for an artist.
an introductory interjection
3. As if he had never seen one before, Jerry stared at the beautiful pyramid.
an introductory adverbial clause
4. Cambodia, an interesting country, is located in southeast Asia.
an appositive
5. The Eustachian a tube is, of course, essential for correct hearing.
a parenthetical expression