下腰椎黄韧带增厚，钙化主要引起（）。
A.脊髓受压
B.神经受压
C.椎板受压
D.椎管狭窄
E.椎间孔狭窄
参考答案：D
They went to the hills and they _____ a good time there last week. [ ]
A. have
B. had
C. are having
D. have had
以下属于长期负债的是( )。
A．应付股利
B．预提费用
C．待摊费用
D．应付债券
