— Are you feeling sad?
— ____________. ( )
A:No.
B:No, I don't.
C:Yes, l do.
抛物线y=a(x+1)(x﹣3)(a≠0)的对称轴是直线____ .
—Who is that woman?
—She is my mother.
我国是人民当家作主的社会主义国家。( )