——What youlast week?——I bought a bagA. did; buy B. did; boughtC. do; buyD. do; bought

问题补充：

——What youlast week?——I bought a bag

A. did; buy

B. did; bought

C. do; buy

D. do; bought

答案：

(答案→)A. did; buy

B. did; bought

C. do; buy

D. do; bought

解析：句意：上周你买了什么？——我买了一个包。结合语境可知上文问的是过去发生的动作，故用一般现在时态。一般过去时态疑问句中，一般由助动词体现时态，行为动词用原形，故选A。