Schematic diagram of some movements of the earth

(1) This picture is a schematic diagram of the earth's revolution; The period of the earth's revolution is one year;

(2) The direction of the earth's revolution is from west to east, as shown:

(3) Combined with the chart: When the earth revolves to position B (around June 22), the direct point of the sun is on the tropic of cancer, and at this time, the northern hemisphere gets the most solar light and heat; This is the summer solstice in the northern hemisphere;

(4) Around September 23, the earth revolves to position C, the direct point of the sun is on the equator, and the world is divided equally between day and night; The seasons in the northern and southern hemispheres are just the opposite;

(5) Quanzhou is located in the northern hemisphere, which has the shortest day and the longest night when the earth revolves to position D;

(6) The rotation of the earth produces the phenomenon of day and night alternation.

So, the answer is: (1) revolution; ? 1 year; (2) ; ? (3)B； ? Summer solstice; ? 6; 22; ? (4)C； ? Equator; ? Conversely; (5)D； ? (6) Day and night alternate.