Not too sure, but I take it that the book satisfies his need for imagination temporarily, but also awakens a tier of satisfaction to be met, be it for more imagination or not.
"All of a sudden..." is a transition that shows suspense. It says something happened, but it didn't happen with any warning and it doesn't tell the reader up front what went on or if it was good or bad.
Answer:
showed, reveal expose, etc
Explanation:
He wants to skip school so he can fish.
