The predicate adjective here is "refreshing".
A predicate adjective is the word that modifies the subject of a sentence (and is an adjective). So for example subject is x, or subject looks x with the x as the predicate adjective
Answer:
How do kaleidoscopes work?
Explanation:
The title is How they work so it makes sense to ask how do they work since that is what you'll be learning about if you were to read the passage.
He wrote you a letter yesterday.
