男，60岁，间歇性跛行6年。下蹲时疼痛减轻，骑自行车正常。直腿抬高试验阴性。X线片显示：腰椎骨质增生明显。最可能的诊断是
A. 腰椎管狭窄症
B. 腰椎问盘突出症
C. 慢性腰肌劳损
D. 棘间韧带损伤
E. 腰椎结核
根据目前所知，古生菌是生物进化阶段中最早出现的原核生物。()
The lifting pressure of ____ is set in the presence of a Surveyor it is locked and cannot
A. fuel valves of main engine
B. injector pump of main engine
C. safety valves of marine boiler
D. safety valves of a reciprocating pump
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