A man being sometimes more generous when he has but a little money than when he has plenty ,perhaps thro's fear of being

问题描述:

A man being sometimes more generous when he has but a little money than when he has plenty ,perhaps thro's fear of being thought to have but little.
问:
1 A man being.为什么要用being?
2 perhaps后面是一个并列句吗?perhaps是并列连词吗?

用being...是现在分词短语作定语修饰a man;
perhaps后面是并列句.