问题补充：
The red skirtby the beautiful girl yesterday.
A. is bought
B. was bought
C. bought
D. is buyed
答案：
A. is bought
(答案→)B. was bought
C. bought
D. is buyed
解析：句意：这件红色的裙子昨天被一个漂亮的女孩买走了。主语skirt与谓语动词是被动关系，用被动语气，系动词be+动词过去分词；而且是已经发生的事情，所以be用过去式was，故选B。
