His friends asked him ________ up smoking.
A:give
B:to give
C:gave
D:giving
用CO合成甲醇的化学方程式为:CO(g)+2H2(g)⇌CH3OH(g)△H<0,按照相同的物质的量投料,测得CO在不同温度下的平衡转化率与压强的关系如图所示.下列说法正确的是( )
已知函数fx=sinx+cosx2+cos2x
如图,抛物线y=ax2+bx+c的图象经过点A(﹣2,0),点B(4,0),点D(2,4),与y轴交于点C,作直线BC,连接AC,CD.