One thing’s for sure, the fire _____by some cigarette butts.

A．might cause

B．could have caused

C．must have been caused

D．should be caused

下列哪项是胆管癌的直接征象

A．扩张胆总管的远端显示实性结节
B．阻塞近端胆管明显扩张
C．肝内见多发转移灶
D．肝脏弥漫性肿大
E．肝门区显示肿大淋巴结