[填空题]
Eclipses happen on Earth because of an amkyf-t3u2- ky;or53o wk6fm7i)z c ny sazing coincidence. Calculate,*r wu),(xfb *rb4 tag 2sglvk: using the information insi gt2s:4r)(g albkrwu*bx,*fvde the Front Cover, the angular diameters (in radians) of the Sun and the Moon, as seen on Earth. Sun = $rad$ Moon = $rad$