题干
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?
Amy:____
Cheng Jie: Is he your father?
Amy:____
答案(点此获取答案解析）
B,A,C
（t为参数)点M、N在椭圆上，对应参数分别为 
， 
，则直线MN的斜率为