. Many experts agree that once these treasures are _______ to the air, great harm will be done to them. So they think it better not to unearth the treasures.

A．exposed

B．threatened

C．constructed

D．conserved

下列骨密度检查方法中能同时评价骨结构的方法是

A．X线平片

B．单光子骨密度测定法

C．双能X线骨密度测定法

D．定量CT

E．定量超声