He nodded his head in silence,and his eyes bright with tears.为什么中间的连词and要去掉?

题目

He nodded his head in silence,and his eyes bright with tears.为什么中间的连词and要去掉?
还有一个小问题,I am glad to be working with you 与 I am glad to work with you是一样的意思么?有何区别?
为何说his eyes bright with tears不是一个完整的句子或并列分句？I am glad to be working with you 不是被动句子么？什么情况下可以用I am glad to be working with you 什么情况下说I am glad to work with you？还一个小小的问题，动名词（Ving)放句首的情况与动词原形放句首（祈使句）的情况有何区别？

答案

之所以去掉and 是因为his eyes bright with tears不是一个完整的句子,如果是his eyes were bright with tears的话 就需要保留and了.
be working 是进行时态 表示现在就在和他一起工作着呢