20期计划3倍投方案

简介：Su Can knows that the length of the day in summer is directly related to latitude. The closer to the poles, the more obvious it is. It is not obvious near the equator. This is related to the spherical surface, because the sun shines for a long time in summer, and it starts to get dark at 5 pm in autumn. , it doesn’t get bright until 7 o’clock in the morning.