腰椎间盘突出最重要的体征是
A．椎间隙压痛B．椎旁压痛C．直腿抬高试验阳性D．直腿抬高试验及加强试验阳性E．腰椎棘突歪斜
参考答案：D
Cars cause most of Beijing's air pollution. So the "No Car Day"campaign (活动) asks Beijing drivers
_____ their cars at home one day each month.[ ]
A. leave
B. leaving
C. to leave
D. to be left
铸造生产在工业中得到广泛的应用。在一般机器中，铸件占整个机器重量的 ( )。
A．10%
B．20%
C．40%～90%
D．50%～80%
