A:①④③②
B:④③①②
C:④①③②
D:①③④②
A. What are you going to take?
B. Where are you going to go?
C. Who is going to go?
D. When are you going to go?
Jenny:____?
Tony: I'm going to go to Beijing.
Gogo: Clothes, shoes....
Tony:____?
Gogo: At six o'clock tomorrow morning.
Gogo: It's me.
已知抛物线C:x2=2py(p>0)的焦点为F,直线2x﹣y+2=0交抛物线C于A,B两点,P是线段AB的中点,过P作x轴的垂线交抛物线C于点Q.
(1)若直线AB过焦点F,求|AF|•|BF|的值;
(2)是否存在实数p,使得以线段AB为直径的圆过Q点?若存在,求出p的值;若不存在,说明理由.
这一天北极的昼夜长短情况是( )