Everyone and students will draw the day and night distribution map of the earth at the vernal equinox, summer solstice and winter solstice in their next assignment 1.

(1) According to the picture, solar term A is summer solstice, solar term B is autumnal equinox, solar term C is winter solstice and solar term D is vernal equinox; (2) The revolution direction of the earth is from west to east; (3) At the autumnal equinox, the earth should be located at point B, and the sun is facing the equator. At this time, the length of day and night around the world is equally divided; (4) When the earth turns to C, the latitude of direct sunlight is 23.5 S, and the relationship between day and night in the northern hemisphere is short in day and long in night. So the answer is: (1) (2) (3) b; Equator; Divide day and night equally; (4)23.5S； (4) The days are short and the nights are long.