“Quickly” is an adverb that is used to indicate the speed of the action being described. In this case, it tells us how the act of running is being performed—quickly.

“Running” is a verb. In this context, it refers to the physical activity of moving swiftly or at speed, using one’s feet. 

So "quickly" is an adverb and "running" is a verb.
识别“quickly running”短语中的词性。