[填空题]
Eclipses happen on Earth because of an amazing coint2) w -my1w7 jx3ut ;nytx-fmccidence. Calculaten5 guh)9uzwt 9, using the i9twu9h5nzg u) nformation inside the Front Cover, the angular diameters (in radians) of the Sun and the Moon, as seen on Earth. Sun = $rad$ Moon = $rad$