脊柱活动度最大的椎体是（）。
A.颈椎和腰椎
B.颈椎和胸椎
C.腰椎和骶椎
D.胸椎和腰椎
E.胸椎
参考答案：A
— Can you come and play football with me?
— __________. But I have a lot of work to do.[ ]
A. I hope not
B. I'd like to
C. I can't wait
D. Of course I can
在焊接回路串联镇定电阻以获得下降外特性的直流电焊机多制成多站式，其国产型号是（）
A.AX7—500
B.AXl—165
C.AX4—300
D.AP一1000
