脊柱有四个生理弯曲，包括颈曲、胸曲、腰曲及骶曲。其中与坐姿舒适性直接相关的是（）。
A.颈曲
B.腰曲
C.胸曲
D.骶曲
参考答案：B
— Got your driving license?
— No. I ________ too busy to have enough practice, so I didn't take the driving test last week.[ ]
A. was
B. am
C. have been
D. had been
颁发接收证书之日即为( )。
A．竣工日B．合同解除日C．缺陷责任期结束日D．完工日
