--I don't think we have met before.--Yes once at a party but we.A. weren't introducedB.

问题补充：

--I don think we have met before.

--Yes, once at a party, but we.

A. weren introduced

B. didn introduce

C. haven introduced

D. were not introducing

答案：

(答案→)A. weren introduced

B. didn introduce

C. haven introduced

D. were not introducing

解析：本题是动词的语态考查。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。”