抛物线y=ax2+bx+c(a≠0)与x轴的交点是(-2,0)和(4,0),这条抛物线的对称轴是( )
A:直线x=1
B:直线x=-1
C:直线x=2
D:直线x=-2
如图a,b,c,d是距凸透镜不同距离的四个点,F为焦点,下列说法不正确的是( )
下列说法错误的是( )
----Mum, Can I have something______? ----Oh, dear . You can only drink some water. There is _____in the kitchen.