tracesn.痕迹；遗迹名词trace的复数形式.tracen.痕迹；微量；踪迹v.追踪；描绘；找出根源trace survey线索调查trace method示踪法trace fossil踪迹化石trace origin追溯起源trace iodine痕量碘trace record飞行轨迹记录trace metals微量元素trace buffer追踪缓冲区trace vector跟踪向量trace-back回溯