Hardly to sleep when the door.
A. had I gone；someone knocked at
B. I had gone；did someone knock at
C. had I gone；did someone knock at
D. did I go；someone knocked at
网友回答
(答案→)A. had I gone；someone knocked at
B. I had gone；did someone knock at
C. had I gone；did someone knock at
D. did I go；someone knocked at
解析：在Hardly...when...，Scarcely...when...，No sooner...than...引导的句子中，后面的从句不用倒装形式，而前面的主句使用部分倒装形式。此题中的D项虽然从结构上符合要求，但是时态错误，在这几个句型中，when从句或than从句一般使用一般过去时，而前面的主句一般使用过去完成时。此句的意思是“我刚要入睡就听见有人敲门”。