It turns out that this step needs to be completed by lactase in human body, because lactose in lactose-free milk in Shu Hua has been hydrolyzed, so it is better absorbed by human body.
Extended data:
Lactose is the main nutrient in milk, and the content is different in different milk (du is about 7% in human milk and 4.2% in milk). Almost everyone can have enough lactase in infancy, but the older they get, the less lactase they will have.
Lactose intolerance is very common in China. Symptoms such as flatulence and diarrhea will appear after drinking milk.