与射线检测方法相比,超声检测的优点是()
A.不受工件表面形状和状态的影响
B.不受工件材质、晶粒度的影响
C.不受缺陷类型、位置和方向的影响
D.缺陷定位比较准确
参考答案:D
I remember that ,an old church on the top of the hill many years ago.[ ]
A. used to be there
B. there used to be
C. there used to have
D. there had
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