Take a look at what went wrong by backtracking and thinking about similar past events.
通过回溯和考虑过去的相似的事件，看一看什么地方出了错。
2
The backtracking method is a kind of optimum-seeking retrieval method by which forward retrieval is done according to the optimum-seeking condition to arrive at the goal.
回溯法是一种选优搜索法，按选优条件向前搜索，以达到目标。
3
Comparing with the outward tracking, the backtracking of "Yiwu-Xinjiang-Europe" cargo train has not realized the normalization of operation. But to those importers, the strength has appeared.