题干
——Do you know Shenzhou X is flying in space?
—— exciting news!
A：What
B：What a
C：How
D：How a
答案(点此获取答案解析）
A
——Do you know Shenzhou X is flying in space?
—— exciting news!
A：What
B：What a
C：How
D：How a
＜
，某时刻在P点为两列波的波峰与波峰相遇，则以下叙述正确的是（ ）
