The poem Dew depicts a drop of dew falling from the sky, turning into a water drop on the lotus leaf and rolling around. It vividly depicts an autumn night, when a drop of dew fell from the sky and landed on the unfolded green lotus leaf, becoming a crystal clear water drop, rolling around, which is really beautiful. "You didn't know the circle from the beginning" means that the author didn't know it was round until he saw the dew rolling around on the surface of the lotus leaf.