— What are you searching the Internet for ?

— I am trying to find out _______.

A．Why is our Chinese ping-pong team able to win every time .

B．How to buy a ticket to Beijing online.

C．When will the new movie The Hobbit II on.

D．How can we protect our environment.

在诊断寰枢关节脱位时，颈椎侧位平片测量寰齿间距应大于

A．2mm

B．3mm

C．4mm

D．5mm

E．6mm