【阅读引入】
阅读理解。阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。
Many traffic jams leave drivers puzzled as they finally reach the end of a tailback to find no visible cause for their delay.Now，a team of mathematicians have found the answer by developing a model to show how major delays occur on our ro
