同学们从一个细胞发育成“小帅哥”、“小美女”让我们看到了生命发生的奇妙变化.
P正三角形ABC所在平面外一点,PA=PB=PC=3,且PA,PB,PC两两垂直,则P到面ABC的距离为( )
下列式子一定是最简二次根式的是( )
﹣As a nurse, her work goes taking care of her patients.
﹣Yes, she always thinks of others.