颈椎椎体骨折最常见于（）。
A.C1~2
B.C2~4
C.C4~5
D.C5~7
E.C7～T1
参考答案：D
---- Do you know _______ they got to know each other?
---- It was last year_______ they both taught Chinese in Scotland.
A．When it was that, when
B．when it was that, while
C．When it was that, that
D．When it was that, as
刮板输送机的刮板链在链轮上掉链如何处理？
