Yao Jizhong School in Suining County, Xuzhou City, Jiangsu Province now arrives at school at 5:20 in the morning, that is, gets up at 4:40.

When I come home from school at 20:30, it's 2 1:00, then I have homework to do and then I have to wash. It was 22 o'clock.

From 22: 00 to 4: 40, the theoretical sleep time is only 6 hours and 40 minutes, and the actual sleep time is only 6 hours.