A:回旋加速器
B:日光灯
C:质谱仪
D:速度选择器
从方框中选择恰当的语句,补全对话。
A.Yes, she is.
B.He's my brother.
C.No, he isn't.
D.He's my brother.
Cheng Jie: Who's that boy?
Amy:____
Cheng Jie: Is she your mother?
Cheng Jie: Is he your father?
水的三态是指____、____、____。