___ to sunlight for too much time will do harm to one's skin.为什么不能用Exposed?

问题描述:

___ to sunlight for too much time will do harm to one's skin.为什么不能用Exposed?
不可以看成是be exposed to 放在句首省略be吗?就像Lost in thought ,he didn't notice me come in.

谓语动词是后面的will do ,这个句子缺的是主语
动名词作主语,而且是被动的 Being exposed
你给的例句是过去分词短语做状语,没看用逗号隔开了?