【题目】—I don't think we have met before.
—Yes, once at a party, but we________．
A.weren't introduced
B.didn't introduce
C.haven't introduced
D.were not introducing

【答案】A
【解析】 introduce是及物动词，后面需要有一个名词。本题中introduce后没有宾语，所以用被动，意思是：但是没有给我们介绍。