sentence: A chef dressed in a white chef's outfit is demonstrating how to sharpen kitchen knives using a tool called Rada knife sharpener. sentence:  He is standing in a kitchen in front of the counter that has a variety of raw vegetables displayed. sentence:  He places a kitchen towel on the counter and then places the knife on top of it. sentence:  He then demonstrates how to use the Rada sharpening tool to sharpen the kitchen knife by running iit back and forth in gentle and steady motion.