John being away,Henry had to do the work.

John being away,Henry had to do the work.
此句是否可改做：John was away,Henry had to do the work.即把句中的动词being改做was可以吗?
我搞不懂的是一个句子什么情况下使用现在分词或过去分词的独立主格结构?就像本句的being我觉得完全可以改做was也同样是完整的句子,为什么非要用being呢?
The other guests had taken advantage of the Queen's absence,and were resting in the shade:however,the moment they saw her,they hurried back to the game,the Queen merely remarking that a moment's delay would cost their lives.
那么本句中的the moment they saw her,they hurried back to the game其间也没用连词，且用逗号隔开的，为做么谓语动词没用动词-ing形式（动词-ing作状语）？