33．It was the first time that Mike______the piano at the concert hall and he hoped that his nervousness would go      ．

A．played；unnoticed

B．had played；unnoticed

C．played；unnoticing

D．had played；unnoticing

脊柱损伤后，跟腱反射消失，膝腱反射正常，可能为脊髓哪一节段损伤（）

A.S₁以下

B.S₂以下

C.L₅以下

D.L₂以下

E.T₁₂以下