问题补充：
in the cage for half a day, the bird became hungry.
A. Being kept
B. Having kept
C. Having been kept
D. Have been kept
答案：
A. Being kept
B. Having kept
(答案→)C. Having been kept
D. Have been kept
解析：这题考查现在分词完成式做状语的用法,因为the bird是被关在笼子里半天了，才感到饿，有先后关系，选C。
