O2是氧化剂;(2)根据(1)的分析,得出:
根据流程,回答下列问题:
根据汉语完成句子
She took her dog with and talked to . There was nobody else next to her.
如图,⊙O中,点A,O,D以及点B,O,C分别在一条直线上,图中弦的条数有( )