问已放入if notEOF和bof，但仍收到错误

EN

Private Sub nav()
        If retVal Then
            lblQuestion.Visible = True

            lblQuestion.Text = rs.Fields("Question").Value
            lblType.Text = rs.Fields("Type").Value
            lblGroup.Text = rs.Fields("Group").Value

            If lblTtype.Text = "d" Then
                txtAnswer.Visible = True
                comboOption.Visible = True
           ElseIf lblTipo.Text = "o" Then
                comboOption.Visible = True
                txtAnswer.Visible = false

            End If
        End If
    End Sub

Private Sub BtnNext_Click(sender As Object, e As EventArgs) Handles btnNext.Click
        If Not rs.EOF Then
            rs.MoveNext()
            nav()
        Else
            MsgBox("This is the last Question")
        End If
    End Sub