Dim n As Integer，a(100)As Integer，max As Integer

  Private Sub Form_Load()      ‘读取原始数据

    Dim conn As New ADODB．Connection．rs As New ADODB．Recordset

    Dim i As Integer

  conn．ConnectionString=”Provider=Microsoft．ACE．OLEDB．12．0；Data

  Source=”&App．Path&。”＼student．accdb”

    conn．Open

    Set rs．ActiveConnection=conn

    rs．Open“SELECT*FROM DF”

    i=0：max=0

    Do While Not rs．EOF

      i=i+1：n=i

      a(i)=         ‘①

      If a(i)>max Then max=a(i)

      rs．MoveNext

    Loop

    rs．Close：conn．Close

  End Sub

  Private Sub Command1_Click()         ‘去重复值排序

    Const t=max

    Dim i As Integer，b(t)As Integer

    For i=1 To n

      B(a(i))=b(a(i))+1

    Next i

    For i=1 To t

       If  Then List1．AddItem Str(t-i+1)       ‘②

    Next i

  End Sub

Dim d(0 To 9) As Integer

s=Text1.Text

c=0

For i=0 To 9

    d(i)=0

Next i

For i=1 To Len(s)

          '填空

Next i

Text2.Text=Str(c)

方框处的代码可由以下三部分组成：

①d(t)=i   ②t=val(Mid(s，i，1))   ③if d(t)<>0 And i-d(t)>c Then c=i-d(t)

代码顺序正确的是(     )