When many people are worried that there are no more heroes in the modern times, two university students who lost their lives to rescue drowning children have shown that heroes still exist. According to the Inner Mongolia Morning Post, the tragedy   on the afternoon of December 14, 2002 when three school students skating on a frozen lake in Qingcheng Park in Hohhot fell through the ice into the freezing water. More than 20 university students who happened to be near the place where it happened immediately went to the rescue of the children. Two children were quickly rescued, but the third died. The child's body was not found for three hours. Two of the rescuers, Liu Ye and Hao Longbiao, also died of cold and tiredness. The body of Hao who took the lead in jumping into the lake was not found until the next day. A student who was unwilling to tell his name said he and his classmates from the local college were taking photos at the lake. When they heard the children's cries for help, they went to the ice hole hand in hand to rescue the children. But the ice kept breaking, causing most of them to fall into the icy water. Local people held mourning ceremonies   at the lake. Eight of the students were seriously affected by the freezing water and were being kept in hospital for further observation  , but their lives were no longer in danger. The author wrote the passage to    _   .
warn people of the danger of skating on ice ask people to learn from the brave university students tell us a tragedy advise university students to cherish   their lives