装车时,货物应当重压轻,有包装的在上,无包装的在下。
参考答案:错
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.
(72)处填()。
A.packets
B.cells
C.message
D.files
白水泥的初凝时间不早于45min,终凝不迟于12h。( )