One day, Justin decided to spend the holiday with his old friend Andrew in Australia. Their plane arrived in Sydney at ten in the morning. They had a good rest in a hotel. The next morning they rented(租)a car and began their travel. Justin found a river and they drove the car there quickly. Soon they got to the river. Before they jumped into the water, Andrew saw a boy playing under a big tree. He asked, “Are there any crocodiles(鳄鱼)in the river? ”“No, there aren't, ”answered the boy. So they began to swim in the river. After a while, Justin felt something hit against(撞击)his leg. He told Andrew about it. They wereafraidand stopped swimming. Andrew asked the boy loudly, “Is it true that there aren't any crocodiles in the river? ”

“Yes, sir, ”said the boy, “But there are many sharks(鲨鱼)in the river. ”