Hearing a scream I rushed downstairs onlythe hostess lying unconscious on the floor.A. s

问题补充：

Hearing a scream, I rushed downstairs, onlythe hostess lying unconscious on the floor.

A. seeing

B. having seen

C. seen

D. to see

答案：

A. seeing

B. having seen

C. seen

(答案→)D. to see

解析：考查不定式做状语。不定式与only连用做状语，表示意料之外的结果；现在分词表示意料之中的结果。句意：听到尖叫声，我冲下楼，发现女主人躺地上，人事不省。这是一个意料之外的结果。故D正确。