unlacing

He stops unlacing and looks at them as if they had appeared there of their own accord.

他停下来看着拖鞋，好象它们是自动出现似的。

And the most important is that it is an unlacing supervising apparatus in reception and departure of train under uninterlocking conditions.

而最为主要的，它将是无联锁情况下接发列车安全作业的一个不可缺少的监督设备。