The district time in Alaska Standard Time West 9 is later than Beijing time (East 8) and the time difference is 9 8 = 17 hours, so Beijing time is 12 o'clock, Alaska is 12 o'clock - 17 hours = 19:00 the day before;

Like the continental United States, Alaska uses daylight saving time, that is, daylight saving time, from 2:00 on the second Sunday in March to 2:00 on the first Sunday in November. The regional time in West 8 is later than Beijing time (East 8) and the time difference is 8 8 = 16 hours, so 12 o'clock Beijing time, Alaska is 12 o'clock - 16 hours = 20 o'clock the previous day.