1. D
2. C
3. E
4. B
5. A
Dashes — the lines surrounding “what a pianist” in number one — act as an excellent replacement for parentheses. I personally use them a lot more often. For number two, interjections are words like “Oh, ah, yes, no, wow, ouch, ew, huh,” and since the interjection is being placed at the very beginning directly before the clause and evidently introducing it, that is also why it is called introductory. For number three, appositives are phrases or other words that rename a noun. “An interesting country” is being used to rename “Cambodia.” A set of commas always separates appositives, as you can see in the sentence, and are always next to the noun the appositive is renaming. For number five, phrases like: “of course, though, by the way” can be used in the middle of a thought to interrupt it for a second before returning to the rest of the sentence.