THE JOKE MACHINE

Everyone was in the ground. "I've got a good joke," said　Wilf. "What goes black, white, black, white?""A penguin rolling down a hill!"
They tell each other jokes whole day in the school. At one time, they got an great idea to raise money for help the children Day.
 I read this book "The joke Machine". This is little bit long, but easy to understand!
This book was written by Roderick.H.

 vocabulary

snap: ぱちんと鳴らす

groan: うめき、唸り声