. The man is said to have worked as a spy in the s, when he ____ information for the government. A. was gathered B. gathered C. had gathered D. has gathered 答案:B(8分)为了安全,在高速公路上行驶的汽车之间应保持必要的距离.已知某段高速公路的最高限速υ = 108km/h,假设前方车辆突然停止,后面车辆司机从发现这一情况起,经操纵刹车到汽车开始减速经历的时间(即反应时间)t = 0.50s。若刹车时汽车受到阻力的大小为汽车重力的k = 0.50倍,取g = 10m/s2,则该段高速公路上汽车间的距离s至少应为多少?