VB操作ACCESS数据库的有关问题

 '我想把a表中的3个字段的内容全部复制到b表中，但是这样不行啊，请大家帮帮忙
    Dim cnn As New ADODB.Connection
    Dim rst As New ADODB.Connection
    Dim tem_id As Double
    Dim tem_name As Double
    Dim tem_num As Integer

Set rst = cnn.Execute("select * from a")
        rst.MoveFirst
        If Not rst.EOF Then
            Set rst = cnn.Execute("select id from a")
            tem_id = rst(0).value
            Set rst = cnn.Execute("select name from a")
            tem_name = rst(0).value
            Set rst = cnn.Execute("select num from a")
            tem_num = rst(0).value
            cnn.Execute ("INSERT INTO b (id,name , num) VALUES (" & tem_id & "," & tem_name & "," & tem_num & ")")
            rst.MoveNext
        End If