（）的依据是国家和地方按照一定原则在一定时期内所下达的主要污染物排放总量控制指标。 ["环境容量控制","目标总量控制","指令总量控制","最佳技术经济总量控制"]
Which of the following logical volume placement policies is likely to give the best performance in most cases， all other factors being equal？（） [" INTRA-POLICY set to ’edge’， INTER-POLICY set to maximum"," INTRA-POLICY set to ’center’， INTER-POLICY set to maximum"," INTRA-POLICY set to ’middle’， INTER-POLICY set to minimum"," INTRA-POLICY set to ’center’， INTER-POLICY set to minimum"]
保额递增型保单的保额随着保单年度的增加而增加，它适用于（）。 ["债权人购买","债务人购买","预期通货膨胀者购买","预期通货紧缩者购买"]
政治环境和经济环境对中低层公共事业管理的影响的特点是（）。 ["间接迂回","复杂直接","巨大","没有影响"]
Which of the following class addresses is reserved for multicast？（） [" Class A"," Class B"," Class C"," Class D"]
简述变流系统主要由哪几部分组成,并描述其功能.
