all those present _______ he began his lecture.

问题描述:

all those present _______ he began his lecture.
When all those present ___ he began his lecture.
A.sit B.set C.seated D.were seated
这题选c还是d啊,为什么?

D be seated表示“就座”.句意:当所有出席者就座后,他开始讲课.