This question requires you to draw the terminator line with a globe (the terminator line is a circle that must cross the equator in the north-south direction, so it can be drawn, hehe). Then, you find the intersection of the terminator line and the equator, the Tropic of Cancer, 30 degrees north latitude, 40 degrees north latitude and 60 degrees north latitude (except the equator, other latitudes can be chosen at will, and the degree is uncertain, so it is convenient to find which one). The next step is to find out the arcs formed by these selected parallel lines cut by dawn and dusk, which represent the daytime line segments (arc AB), and the midpoint of each arc is the latitude 12 point (point C). Then you will find that the termination line only intersects the equator, and the distance from point A to point C (arc AC) = the distance from point B to point C (arc CB), which shows that only on the equator, any season is sunrise at 6 o'clock, 18 sunset (this can also be deduced), which is symmetrical with 12 at noon. Elsewhere, arc AC and arc CB are also equal, that is, they are both symmetrical with the point 12! ! ! The problem comes out, so why not actually? Take Shanghai as an example. In fact, Shanghai's "12" point is not what we call local time 12, that is, it is not our point C. For the sake of national reunification, Shanghai also adopts the East Eighth District Time in Beijing Time Zone. In fact, when Shanghai "12 o'clock" (Beijing happens to be 12 o'clock), it has actually passed 12 o'clock local time, because Shanghai is in the east of Beijing and the time is earlier than Beijing, just as Tokyo time is earlier than Beijing. This is what we call jet lag. This is a geographical phenomenon and the result of the earth's rotation. Hehe, love the earth, love geography and love life!