gray type造句

• By applying the gray system theory , three indexes of road traffic safety are induced and calculated to categorize the gray type of cities to more rationally evaluate the situation of traffic safety
  应用灰色系统理论对道路交通安全的3项指标进行归纳和计算，从而判断各城市所属的灰类，更合理地评价各城市的交通安全状况。