While I_______ a detective story, someone_______ at the door．
A. read, was knocking
B. read, knocked
C. was reading, knocked
D. was reading, was knocking
While I_______ a detective story, someone_______ at the door．
A. read, was knocking
B. read, knocked
C. was reading, knocked
D. was reading, was knocking
C
【解析】
试题分析：句意:我在读一篇侦探小说时，有人敲门了。根据题干语境while从句的动作应是正在进行，主句的动作应该是一般过去时，故选C。
考点：考查过去时态。