A.系统抽样.整群抽样.偶遇抽样.简单随机抽样
B.单阶段抽样.多阶段抽样.雪球抽样.便利抽样
C.简单随机抽样.分层抽样.整群抽样.配额抽样
D.简单随机抽样.分层抽样.系统抽样.整群抽样
E.多阶段抽样.分层抽样.系统抽样.机械抽样