It is said that the early European playing-cards ______ for entertainment and education.

It is said that the early European playing-cards ______ for entertainment and education.

A.were being designed

B.have designed

C.have been designed

D.were designed

答案及解析： D

解析：

early暗示该空表示“过去被设计”，应填一般过去时被动语态动词形式were designed。