How to judge solar terms according to the bisection of the earth's revolution

It's simple. Look at the picture. When the sun shines directly on the equator, it is the vernal equinox or autumnal equinox. You can also look at the length of day and night in the northern and southern hemispheres. If day and night are equal in length, it is also the vernal equinox or autumn equinox. When the sun shines directly on the Tropic of Cancer, it is the summer solstice, and you can also see the Arctic Circle. If you are in the Arctic Circle all day, it is also the summer solstice. When the sun shines directly on the tropic of Capricorn, it is the winter solstice, and you can also see the Antarctic circle. If the Antarctic circle is daytime, it is also the winter solstice.