He was told to keep the lead car at a constant and safe distance. 他被要求与引导车保持一个恒定而安全的距离。
Based on the analysis of their characteristics and functions, this paper tries to explore the possible ways to educate and guide these groups to serve the whole class effectively. 分析高校班级中非正式群体的特点及作用，可以探讨如何教育与引导这些非正式群体，使之更好地为班级的整体目标服务。
