正常肝内胆管分支的直径应当为：
A．<2mm
B．<3mm
C．<4mm
D．<5mm
E．<6mm
参考答案：B
—Who is laughing in the room?
— _____ must be Lucy.
A. She
B. It
C. This
D. He
重型四面刨床一般是指有七、八根刀轴，加工工件宽度为（）以上的四面刨床。
A.100mm
B.200mm
C.300mm
D.400mm
