诊断椎管内肿瘤最可靠的根据是（）。

A.腰椎穿刺示压颈试验完全梗阻

B.脑脊液蛋白增高

C.脊髓造影所见

D.脊柱X线平片所见

E.脊髓同位素扫描

The employees _______that they should renew their contracts within a week.

A．advise

B．have advised

C．are advised

D．had been advised