Mary’s mother was very angry with her.She left the room without a word.
A:saying
B:say
C:to say
D:said
日常生活中的下列变化一定发生化学变化的是( )
将圆x2+y2=1 每一点的,横坐标保持不变,纵坐标变为原来的2倍,得到曲线C.