All speakers were confident, comfortable with being seen.
with是介词，with being seen是什么结构？
All speakers wereconfident, comfortable with being seen.
with 是介词，being seen 是动名词（被动形式）作介宾。
be comfortable with...的意思：comfortale 是“舒适的”，with指“缘由”。字面：因......而舒适。因某事而舒适，自然会满足于某事，乐于做某事。引申为“乐于让人看到”。
All speakers wereconfident, comfortable with being seen. 所有些演讲者都非常自信，乐于让人看到。