同意曾老师解答

(1)come doing sth 为现在分词作方式状语，说明come动作发生的方式

She just flutters her eyelashes and the men come running!  

她只要眨一下眼睫毛，男人们便忙不迭地跑过来！

He expects his wife to come running every time he wants something.  

他希望妻子对他的每个要求都欣然顺从.

The children come running hotfoot when they hear tea is ready.  

孩子们听说茶点已准备好了,便赶紧跑过来.

If you offer the children rewards for helping they'll all come running. 要是让孩子帮忙做事,给他们点儿奖品,他们就巴不得都来帮忙了.

(2)come to do sth为动词不定式作目的状语，相当于come and do sth结构

What have they all come to do, here in the market - place ? "  

他们都到这市场上来干嘛 呢 ? ”

We fervidly a zonal clients come to do business with us.  

我们热切欢迎国内外新老客户前来洽谈业务.

You come to do explain it.  

你来解释一下.