腰痛最常见的原因是()
A．腰椎间盘突出症
B．腰肌劳损
C．腰椎骨折
D．第三腰椎横突过长
E．肾、输尿管结石
参考答案：B
—I've _______ using plastic bags when shopping.
—You' re right. It' s good for our environment. [ ]
A. stopped
B. finished
C. started
D. enjoyed
加热炉的工艺联锁有（）。
A、炉膛温度高联锁
B、原料低流量联锁
C、入炉空气温度低联锁
D、氧含量高联锁
