There was no sign they had died from diseases such as bird flu - the main worry in such cases. Among the theories was a truck had collided（碰撞）with the crowd.
A. /; that
B. that; that
C. that; which
D. that; /
网友回答
A. /; that
(答案→)B. that; that
C. that; which
D. that; /
解析：考察名词性从句。本题第一空使用that引导同位语从句that they had died from diseases such as bird flu解释前面的名词sign的内容。第二空that引导的是一个主语从句that a truck had collided（碰撞）with the crowd, that在句中不充当任何成分，只起引导和连接的作用。句意：没有他们死于禽流感的迹象，禽流感是这个地区的最主要担心的死亡的原因。在这些原因里，一辆卡车撞上了人群。故B正确。