关于气管的分支顺序，下列叙述正确的是（） A.主支气管-段支气管-肺叶支气管-呼吸性

0P101的实收总金额原则上不允许更改，确实是笔误而必须更改的，在更改后必须由（），（）和（）共同确认并签章。

Marry _____ as a secretary in this company for twenty years and now she stays at home taking care of her own garden.

A．has served

B．had served

C．has been served

D．served

September 18,1913 is the day ______we'll never forget.[ ]

A. that       

B. when     

C. on which   

D. on that

上下牙可起磨碎食物的结构是（）。

A.牙尖与牙尖

B.牙尖与三角嵴

C.牙尖与边缘嵴

D.牙尖与窝

E.以上都是