During this time,the passengers were told to keep calm until they had disembarked.
问题描述：
During this time,the passengers were told to keep calm until they had disembarked.
为什么用过去完成时?先被告知保持冷静,然后下船的.
答
首先翻译下这句话 在这段时间中 旅客被告知需保持冷静直等到下车前
那么可知只有当下车即disembark这一动作完成后keep calm这一动作才结束
因此选择完成时
因为原文中是were 也就是过去式 所以完成时也应用过去的相应时态 即过去完成时