题干
________ soccer in the street. It's too dangerous.
A：Not play
B：No play
C：Don't play
D：Not to play
答案(点此获取答案解析）
C
________ soccer in the street. It's too dangerous.
A：Not play
B：No play
C：Don't play
D：Not to play
，则a与b夹角为（ ）
