Books like Clifford's Sports Day
Norman Bridwell
Clifford's Sports Day is 31 pages, about 34 minutes at 250 words a minute.
7 books to read next
How long each takes
Spot Goes to School 22 min 
A Time to Embrace 6.0 h 
The Intelligence of Dogs 5.0 h 
Captain Underpants and the Big, Bad Battle of the Bionic Booger Boy, Part 2 3.2 h 
The Miscalculations of Lightning Girl 5.5 h 
King Arthur 1.1 h 
Timothy Goes to School 35 min Bar height shows length. Estimated at 250 words a minute.