4.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
网友回答
A. were being designed
B. have designed
C. have been designed
(答案→)D. were designed
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。