She listened with aexpression on her face which suggested she didn’t completely understand

问题补充：

She listened with aexpression on her face,which suggested she didn’t completely understand.

A. puzzling

B. frightened

C. frightening

D. puzzled

答案：

A. puzzling

B. frightened

C. frightening

(答案→)D. puzzled

解析：考查形容词。A令人不解的；B令人害怕的；C害怕的；D不解的。句意：她带着不解的表情听着，表明了她没有完全理解。