题目

It's reported that many people died of traffic accidents each year. Road safety has aroused the widely attention of the public. Many rules have made to reduce the traffic crashes, especially for the ones involved in the pedestrians. In my opinion, we should make road safety seriously in our daily life. While used the road, we must walk on the pavement and learn to protect us. Besides, car drivers should obey the traffic rules, that is both good for themselves and others. In the word, obeying the traffic rules are what all of us should pay attention to particularly. After all, life is n当m＝2，n＝1时，多项式等于 [　　] A．1B．9 C．3D．5