Once upon a time, there was a poor man. One day, after working for hours, he had a rest under a tree in the middle of the field. Just then, he saw a terrible snake coming out of an anthill . The man thought that the snake might be the god of the field. He did not give it anything, so he could not get anything from the field. At once he went to bring a bowl of milk and offered the milk to the snake. "God of the field! I didn't know that you live here. That's why I never gave you anything. Please _ me. " Then he went home. The next day, when the man came, he found a gold coin in the bowl near the anthill. From then on, the man gave milk to the snake and found gold coins. One day the man was so busy that he couldn't send milk to the snake. So he asked his son to take care of the snake. The son brought milk to the anthill and gave it to the snake. The next day, when he came back, he found a gold coin in the bowl. After taking the gold coin, he thought, "This anthill must be full of gold coins. I would kill the snake and take them all." The next day, the son came to the field with milk and a stick. He gave the milk to the snake and hit it with the stick. The snake escaped the stick and bit the boy to death. From the passage we can learn that  _  .
too much greed  is harmful we should protect the snake the snake is terrible people can't get coins from the snake