The submarine crew was taking part in training activities Wednesday but failed to report to a planned meeting.

潜艇上的船员周三正在参加训练活动，但是没有按计划进行会议汇报。

So a submarine crew gauges what's around them by determining how long it takes to echo back to them.

因此，潜艇上的工作人员通过确定回声需要多长时间来测量周围的环境。