He told us he a concert .
A. had attended；three days before
B. attended；a week ago
C. would attend；since a week ago
D. was attending；for a week
网友回答
(答案→)A. had attended；three days before
B. attended；a week ago
C. would attend；since a week ago
D. was attending；for a week
解析：主句He told us用的一般过去时态，而从句动作参加音乐会发生在主句谓语动词之前，所以从句要用过去完成时态。选A。