[填空题]
Eclipses happen on Earth because olj.gbi 0hl- n(gzo2nk g9 yj7-f an amazing coincidence. Calcul+o )yxnzwc2. hb5uo -oate, using the information inside the Front Cover, the angular diameters (in radians) of to5hy o-.wu o2z) b+xnche Sun and the Moon, as seen on Earth. Sun = $rad$ Moon = $rad$