----before we depart tomorrow,we should have a wonderfui dinnerparty.Ahad they arrived

问题描述:

----before we depart tomorrow,we should have a wonderfui dinnerparty.Ahad they arrived
Bwould they arriveCwere they arriving Dwere they to arrive

D were they to arrive
were they to arrive=If they were to arrive 是对将来情况的虚拟.
句意:如果他们明天在我们离开之前到达,我们就举行一个精彩的宴会.