According to the latest reports on TV and in the newspaper, food safety is becoming a ____________ serious worldwide problem.

A．more and more

B．little by little

C．now and then

D．one by one

叉车、装载机的车桥与车架之间常用（）系统。

A、弹性悬架

B、刚性悬架

C、无悬架

D、挠性悬架