铣削尖齿形离合器常采用（）铣刀。铣刀的角度要与尖齿形离合器的槽形角相吻合。
A.盘形三面刃
B.立铣
C.对称双角
D.专用成形
参考答案：C
下列关于胆管癌的描述，哪项正确
A．下段发病率最高
B．病理组织大多是腺鳞癌
C．癌肿生长缓慢，极少发生远处转移
D．放射治疗敏感
Questions 27-30
A． It is a new one with only 2 editors.
B．It takes him on the permanent staff.
C．It controls the final look of his works.
D．It has a nurturing environment.
