Read the picture and answer questions 45 ~ 46. Xiaoming, who lives in Liwan District, feels that the weather is getting colder every day, and the night is coming earlier every day ...

When the earth revolves around the sun, the axis of the earth has a fixed inclination angle of 66.5 with the plane of the orbit, which makes the direct point of the sun's rays regularly move between the tropic of cancer in a year.

When the sun's rays directly hit the equator, it is the vernal equinox or autumnal equinox in the northern hemisphere; When the sun shines directly on the tropic of cancer, it is the summer solstice in the northern hemisphere; When the sun shines directly on the tropic of Capricorn, it is the winter solstice day in the northern hemisphere.

Combined with the title "The weather is getting colder every day, and the night is coming earlier every day", it shows that the days are getting shorter and the temperature is slowly decreasing. According to the diagram, the region is running between ② and ③ at this time. < P > Therefore, B. 。