_I had just started back for the house to change my clothesI heard voices.A. asB. whenC. a

问题补充：

_I had just started back for the house to change my clothesI heard voices.

A. as

B. when

C. after

D. while

答案：

A. as

(答案→)B. when

C. after

D. while

解析：考查连词。并列连词when的意思是“这时（突然）……”，与前面的just呼应。