A:a
B:b
C:c
D:d
请你摘下满天星.
(提示:NaHCO3+HCl→NaCl+H2O+CO2↑)
— I'm looking_ the kids. They should be back for lunch now.
已知抛物线y=ax2+bx+c如图所示,则下列结论中,正确的是( )