使用ado控件怎么关闭access数据库？详细代码

On Error Resume Next
Dim cnn As ADODB.Connection
Dim cmd As ADODB.Command
Dim rst As ADODB.Recordset
Set cnn = New ADODB.Connection
cnn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;……"
cnn.Open
Set cmd = New ADODB.Command
Set cmd.ActiveConnection = cnn
cmd.CommandType = adCmdText
cmd.CommandText = "SELECT A.* FROM A"
Set rst = New ADODB.Recordset
rst.CursorLocation = adUseClient
rst.CursorType = adOpenDynamic
rst.LockType = adLockOptimistic
rst.Open cmd
Zone = rst.Fields(1)