分类：教育/科学-外语学习-英语考试
问题：who_______itughtb.didbuy 
who_______  ught b.did buy
回答：选A buy的过去式是bought嘛~没有who did buy it这种句式.除非是Did he buy  it.或者也有he did buy it.did在这里可有可无，表强调