to sunlight for too much time will do harm to one’s skin.A. Exposed 　B. having exposedC.

问题补充：

to sunlight for too much time will do harm to one’s skin.

A. Exposed

B. having exposed

C. Being exposed

D. After being exposed

答案：

A. Exposed

B. having exposed

(答案→)C. Being exposed

D. After being exposed

解析：动名词短语做主语，用系表结构表示状态。