Our English teacher , having explained to us how to design a project, allowed us a whole week’s preparation and then the class.
A. to dismiss
B. dismissed
C. dismissing
D. having dismissed
网友回答
A. to dismiss
(答案→)B. dismissed
C. dismissing
D. having dismissed
解析：考查动词时态。句意：我们音乐老师，和我们解释了怎么设计一个项目后，允许我们一周的准备时间，然后下课了。根据主句动词allowed为一般过去时态，and后的动作是顺成关系，故也用一般过去时。选B。