trace tov.上溯;追溯到
tracen.痕迹;微量;踪迹v.追踪;描绘;找出根源
trace along behind跟在后面
Trace gas detection痕量气体检测
trace of foot joint足关节轨迹
trace elements zinc微量元素锌
trace contamination痕量污染
trace to the sender查寄信人
trace specification轨迹说明
trace metal element微量金属元素
trace oil treatment微量油处理
trace pending fault正处理追踪故障