几个关于非谓语动词的问题

Question

1.Determined to change(下定决心去改变),he entered a diet program.
为什么不用Having determined to change

2.Being exposed to sunlight(暴露在阳光下)for too much time will do harm to your skin.
为什么不用Exposed to sunlight

Answer 1

第一个现在分词的完成时强调动作在谓语动词动作之前就已经完成。这里指原因，不强调顺序。所以用过去分词短语。
第二个过去分词不能做主语，动名词能做主语。

Answer 2

Being exposed to sunlight for too much time 是动名词短语做主语，而
Exposed to sunlight 是现在分词不能做主语。希望对你有帮助。