如图是一个几何体的三视图,正视图和侧视图均为矩形,俯视图中曲线部分为半圆,尺寸如图,则该几何体的全面积为( )
A:2+3π+42
B:2+2π+42
C:8+5π+23
D:6+3π+23
已知抛物线y=x2-4x+3,求出它的对称轴和顶点坐标.
— It's dangerous to swim here. Look at the sign.
— Oh, I notice it. Thanks for telling me.
随着经济的发展,我污染生活也在不断改善,真是“____”。