地球公转、五带形成、太阳直射点回归运动、太阳光线与地面的角度、太阳辐射、极昼与极夜（5.5分）

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VIDEOS
MP4	N/A	480P	Download
MP4	N/A	360P	Download
AUDIO
MP4	N/A	mp4a.40.2	Download
MP4	N/A	mp4a.40.5	Download
MP4	N/A	mp4a.40.2	Download
THUMBNAILS
	JPEG	Origin Image	Download