每周参加勤工助学的总时间不超过（）小时。
A.6
B.8
C.10
D.12
参考答案：B
—Is the woman walked past just now your teacher?
—Yes. She teaches _ English. [ ]
A. that, our
B. who, us
C. whom, us
D. who, our
分娩时，胎头复位及外旋转的角度为( )
A．15°
B．45°
C．50°
D．80°
E．90°
