[填空题]
Eclipses happen on Earth because of ankwbc z:3- du 5h2)rfdiry;za 9 amazing cs dzd9v/4po-c oincidence. Calculate, using the information inside the Front Cover, the angular diameters (in radians) of the Sun azp-ovd94/scd nd the Moon, as seen on Earth. Sun = $rad$ Moon = $rad$