—It's Mid-autumn Day today. Don't forget to give my best wishes to your family.
—__________. Thank you very much.
A:OK, I will
B:Yes, I do
C:No, I won't
D:No, I don't
①a<0; ②b2﹣4ac>0;③2a﹣b=0;④若点P(x0,y0)在抛物线上,则ax02+bx0+c≤a﹣b+c.其中结论正确的是( )
下列疾病中,都属于传染病的是( )
下列事件为不可能事件的是( )