根据短文内容选择最佳答案。

Peter, Ann, Mary and their parents went to the countryside for their summer holiday. That was a beautiful place. They lived in a farmer's house. The farmer was Mr. Black.

In the morning, they went for a walk in a forest. They saw a river. The father wanted to swim in it. So he jumped into the river. After some time, he came out. He said there were a lot of fishes in it. In the afternoon, Peter and Mary went fishing by the river. Two hours later they caught ten fishes. In the evening, Ann cooked the fishes and some other delicious food for dinner. They ate a lot. They were very happy.