[填空题]
Eclipses happen on Earth because of an amazxxa1 bt+x(y1 + nxifmcu)*da1ing coin5,*c90xl1u -nda vui lspz n-qcidence. Calculate, using the information inside the Front Cover, the angular diameters (in radians) of the Sun and t9qsnlcv -p xl0,a-5 dizu*u1nhe Moon, as seen on Earth. Sun = $rad$ Moon = $rad$