A.CANET B.CHINANET C.CERNET D.NCFC
A.1998B.1985C.1990D.1995
A.主域名服務(wù)器(Primary) B.次域名服務(wù)器(Secondary) C.只緩存域名服務(wù)器(Caching-only) D.測試域名服務(wù)器(Test)