其他列车发生冲突、脱轨、火灾或爆炸，造成单线行车中断满4小时并影响其他列车，列（）事故。
A、重大
B、大
C、险性
D、一般
参考答案：A
It is the prevention of disease______its successful treatment that has led to the rapid increase of the world’s population.
A．rather than
B．less than
C．in addition to
D．in the direction of
B尿素循环水设计温差效果为（）。
