题干
Sally is active girl and she enjoys playing volleyball.
A：the
B：a
C：an
答案(点此获取答案解析）
C
Sally is active girl and she enjoys playing volleyball.
A：the
B：a
C：an
，在射线OA、OB上分别取点OA
=OB
，连结A
、B
，∠
，…，∠
= 。