在短文的空格处填入适当的单词

    The lights were , so the old man stopped his car and waited for them to to green. he was waiting, a police car came up behind him，hit his car in the back and stopped. There two policemen in the police car, and they were amazed and glad when the old man got out of his car and walked towards them without any trouble after such an . He was over 70 years old. The old man came to the door of the police car, smiled kindly and said, "Tell me, young men, how do you stop this car when the lights are red and I am not here?”