Does The Sog Know

Once there were two classmates Pat and Tom. One day, Pat went to Tom's house to borrow a book.

On the entrance, he found a dog standing. Seeing Pat, it started barking. Pat got frightened. Tom came running and held his dog. Pat was still breathing heavily

At this, Tom said, "Pat, dogs who bark never bite." Pat said, "you and I know this proverb, but this dog doesn't know." Both the friends laughed heartily.