urgent什么意思,

if you are very urgent to get the price please call us.
urgent
guest from the group had to cut short his tour because of urgent
紧急,应急等这些专业词对应的英文是什么,有没有国际通用的缩写?
data从哪里开始,保留区,ack(是否启用ack,urg(是否启用urgent指针)