用方框中所给单词的适当形式填空。
sing, glass, have, hair, be
A. Why are you sad?
B. Because I got a kitten.
C. Because I did my homework very slowly.
如图是由射线AB,BC,CD,DE,EA组成的平面图形,则∠1+∠2+∠3+∠4+∠5=____ .