英语语法问题，以ing开头的分句是什么语法结构

你的例子中，reflecting 及后面整个部分叫做伴随行为，即他在says的同时在做的另外一件事。再举个几个好懂的例子：

He stood by the window, looking out the window.

I walked in the yard, thinking about those old days in this house with my family.

ing部分前面和可以加一个主语，这是仍然表示伴随行为，如

She was running along, her long hair waving in the air.