why did you come so late?the bus was crowed.we were kept for half an hour.为什么用were kept?
问题描述：
why did you come so late?the bus was crowed.we were kept for half an hour.为什么用were kept?
答
be+did 是被动语态
这句话的意思是说
你为什么来得这么晚?公交车太挤了,我们等了半个小时.
其实可以理解为我们被耽误了半小时.