Geographical interpretation of the twenty-four solar terms

The first question is beginning of spring and beginning of winter, and the second question is four kinds of awns or heavy snow. The first question is, Beijing is north of the Tropic of Cancer, and the longest and shortest day of sunshine is the summer solstice or the winter solstice. If the sunshine time is similar, the direct point of the sun must be symmetrical on both sides of the summer solstice or winter solstice. Qingming corresponds to the White Dew, Grain Rain corresponds to the intense heat, fright corresponds to the cold dew, and rain corresponds to the first frost. The first question obviously corresponds to beginning of winter and beginning of spring, so choose B, and let's look at the second question. First of all, understand what this picture means. We know that the terminator line immediately separates the night and day of the earth at a certain moment. When the direct point of the sun is on the equator, it is also the vernal equinox and the autumnal equinox, which is equivalent to the sun shining on the earth. The terminator line is perpendicular to the equator and must intersect with the North Pole at 90 degrees north latitude, so the solar terms at this time are vernal equinox or autumnal equinox. When the direct point is located in the Tropic of Cancer, the termination line begins to swing from side to side, no longer perpendicular to the equator, the included angle between the equator becomes smaller, and its north and south vertices begin to shift to the polar circle, that is, 68.5 degrees north latitude, that is, the summer solstice or winter solstice. So that we can understand what Figure B means. Suppose two 90-degree points and two 68.5-degree points are the vernal equinox and the winter and summer solstice respectively. Let's look at one first. Assuming that 68.5 degrees before 1 is the summer solstice, the position of heavy snow should have passed the autumnal equinox of 90 degrees. If this is the winter solstice, it can't be the university solstice before winter, so A is wrong. By analogy, 2 o'clock is Changxia or beginning of winter, 3 o'clock is winter solstice or summer solstice, and 4 o'clock is correct, so choose D.

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