About two year ago, it is my first time to left university and return home. I bought a train tickets, the price of which is suitable for me. I came to the train station and waited for train. suddenly, I realized that I could not find my ID card. In China, if you do not bring ID card, the staff do not allow you to take the train. I did not go with my friend so I felt scared when I found this fact. Fortunately, a policeman on duty at the train station found me looks anxious and asked me what happened. I told him the problem. Then he advised me to call my roommates to make sure if I leave my ID card in dormitory. However, my roommates said no. the condition seemed to be more serious. I felt more scared because the train was going to leave. He suggested me that he could help me apply for a temporary ID card so that I could use today. thanks for his advice, I successfully taken the train in the end.