-Betty, long time no see.__________?

-Everything is OK.Thanks.[ ]

A. What are you up to

B. How is it going

C. What is the book

D. What were you doing?

Frankfort plane

A．连接双侧眶下缘最低点和外耳道上缘的一个假想平面
B．从一侧鼻翼中点到同侧耳屏中点的假想连线
C．连接双侧眶下缘最低点和耳屏中点的一个假想平面
D．从一侧口角到同侧耳屏中点的假想连线
E．从上颌中切牙的近中邻接点到双侧第一磨牙的近中颊尖所构成的假想平面