— You speak very good English!

— Thanks. I ______ English in Shandong University for four years.

[      ]

A. study

B. studied

C. was studying

D. had studied

男，68岁，无明显诱因下腰痛伴间歇性跛行3年，影响工作和生活。查体：棘突及棘突旁无明显压痛，腰后伸痛(+)，反侧L征(-)屈颈试验(-)下肢腱反射正常。该病人最可能诊断是()

A．腰肌劳损

B．马尾肿瘤

C．腰椎管狭窄症

D．腰椎间盘突出症

E．腰棘间韧带损伤