—What does Anna look like?
—__________.
A:She's kind
B:She's tall
C:She likes skating
①当|OA|+|OB|最小时,求l的方程.
②当|PA|•|PB|最小时,求l的方程.
— Yes, they are.
美国总统富兰克林·罗斯福、克林顿经济政策的相同点是( )
— It is a library.