[填空题]
Eclipses happen on Earth because zs4wo ,6nw+ e :h4aeskof anphse6lgv o (:8l (kul9 amazing coincidence. Calculate, using the information inside the Front Cover, the angular diameters (in radians) of the Sun and the Moon, as seen on Eu(g869kl: lseo ( hvplarth. Sun = $rad$ Moon = $rad$