He talked a lot about things and persons ________ they remembered in the school.
A:which
B:that
C:whom
D:what
在频率分布直方图中各小长方形的面积表示( )
____
我国的最北端位于( )
一对夫妇第一胎生了个女孩,他们想再生个男孩,那么第二胎生男孩的机会是( )