The two statements that use a metaphor to make a comparison are:
- "When it came to catching tennis balls, the dog was a regular Wimbledon champ."
- "The author’s life was an open book, with each year a different chapter."
The first statement compares the dog's ability to catch tennis balls to a Wimbledon champion, while the second compares the author's life to an open book. Both statements imply a comparison without using "like" or "as," which is characteristic of metaphors.