The woman was about to open the door she heard a strange sound from inside.A. asB. whileC

问题补充：

The woman was about to open the door she heard a strange sound from inside.

A. as

B. while

C. when

D. then

答案：

A. as

B. while

(答案→)C. when

D. then

解析：本题考查连词。句意：那位妇女正要开门,这时她听见里面有奇怪的响声。be about to do..when.. 刚要做……正在这时……。