How to distinguish the terminator line? What problems are involved?

First determine the day and night hemisphere, then follow the direction of the earth's rotation, from night to the morning line of the day, and vice versa.

(1) Early line and faint line. (From west to east, the transition from day to night is the morning line; From west to east, the transition from night to day is a faint line. )

(2) The movement direction of the terminal line and the rotation direction of the earth. The terminal line moves in the opposite direction to the earth's rotation. )

(3) The local time is displayed at the termination line. (local time of morning line = night length /2 = 12 day length /2, local time of faint line = 24 day length = 12+ day length /2. )

(4) Judging seasons and solar terms according to the termination line. (The local time of the morning line is 6 o'clock or the local time of the faint line is 18 o'clock, and the corresponding solar term is vernal equinox; The hemisphere with the morning line local time less than 6 o'clock or the dark line local time greater than 18 o'clock is the summer half year of this hemisphere, and vice versa. )

It includes multiple-choice questions and fill-in-the-blank questions.