Some visitors are amazed at the fact _________ Australia is the only country in the world ______ covers a whole continent.

A．that; that

B．what; which

C．that; whose

D．it; who

强直性脊柱炎骶髂关节X线改变中期表现特点（）

A.关节间隙狭窄

B.关节间隙加宽

C.关节间隙消失

D.髂骨侧骨致密带增宽

E.关节边缘增生与腐蚀交错呈锯齿状