In low-speed network，it is usually adequate to wait for congestion to occur and then react to it bytelling the source of packets to slow down．In high-speed networks，this approach often works poorly，because in the (71) between sending the notification and notification arriving at the source，thousands of additional (72) may arrive．In ATM network，a major tool for preventing (73) is (74) control．When a host wants a new virtual (75) ，it must describe the traffic to be offeredand the service expected．

（74）处填（）。

A．flow

B．admission

C．traffic

D．time

“如果偶然性不起任何作用的话，那么世界历史就会带有非常神秘的性质”。这是一种 ( )。

A．历史宿命论的观点

B．形而上学机械决定论的观点

C．辩证唯物主义决定论的观点

D．唯心主义决定论的观点