博德的事故因果连锁过程包括如下五个因素管理失误；个人原因或工作条件；人的不安全行为或物的不安全状态；事故；伤亡。
参考答案：对
The morning news says a school bus ______ with a train at the junction, and a group of policemen were sent there immediately.
A．bumped
B．crashed
C．collided
D．struck
