Hollow out: cut the knife on both sides, combine the head and tail, and remove the unwanted melon skin in the middle.
Scraping green: here, first draw a line on the melon skin with the tip of a knife as an outline, just like drawing with a pen, only carving green skin, not white meat. Just scrape the green with the outline. Line: the second half of the knife caters to the left and right, and the line naturally comes out.