"Thickening" is also called "greasy" and "sticky". Thickening is made by mixing starch (usually sweet potato powder) with water to make a powder juice. Generally, it is poured into the dish when the dish is almost cooked, and heated to gelatinize the starch, so as to absorb the water in the soup to form a thick, smooth and smooth thickened juice, which makes the soup blend and delicious, keeps the dish crisp and tender, and makes the dish beautiful in appearance and bright in color.