What do you mean by Class Three and Class Two? I saw that the recruitment position was written like this? .

Three shifts refers to a working system that some enterprises can't stop production at night, also known as shift duty. Generally, it is divided into three periods: day shift: 8am-16pm; Night shift:16pm-24pm; Night shift: 0: 00 am the next day-8: 00 am the next day. Enterprises should give corresponding night shift subsidies to employees who work in middle and late shifts, and at the same time, employees should not be allowed to work in shifts because of busy work, which is commonly called "big shift" (two shifts work together).