Every year in Australia there arecrocodile(鳄鱼)attacks(攻击) on humans. Two years ago, a 24-year-old German tourist died when she went  in a lake. Although there were signs warning people that there might be crocodiles, the girl and  friends decided to have a midnight swim. The girl  disappeared and the next morning her body was found. Near it was a four-meter crocodile. And only last month two boys watched in fear as their friend was killed by a crocodile. They were washing their mountain bikes in a river at that time. Then, those two boys climbed a tree and stayed there for 22 while the crocodile waited below.