Mr Smith and his son Yoke rent a boat from Mr Creen. They start to fish but get nothing. They find another place to fish and catch a lot of fish. Now it is late and they are going back home. Yoke says, "I am going to come here again tomorrow." "Yes, I'm coming with you, too,"says his father."But how can we find the same place again?" "I think that's easy. "Yoke says. "Look! I can make a mark on the side of the boat. " His father laughs and says, "No. That's foolish! Mr Green doesn't give us the same boat every time."