编写“英文文章整理”程序，实现如下功能：点击“整理”按钮对任意输入的英文文章进行整理，整理规则为：所有句子开头为大写字母，其他都是小写字母，句子结束符为“.”“?”或“!”；所有标点符号后面都空一格；英文的标点符号都为半角符号。程序运行界面如图所示。

请根据算法将下列程序补充完整。
Private Sub Command1_Click()
Dim Y As String, Z As String, X As String, L As Integer, t As String
Y = ""
X = Text1.Text
L = Len(X)
For i = 1 To L
Z = Mid(X, i, 1)
If Z >= "a" And Z <= "z" Then '第一个是小写，转大写
If i = 1 Then Z = Chr(Asc(Z) - 32)
ElseIf Z = "!" Or Z = "." Or Z = "?" Then '标点后面有一个空格，一个大写
1___________
If t = " " Then i = i + 1
Z = Z & " "  '算空格
If i < L And 2_______________ Then
Z = 3_____________   '后面字母要大写
i = i + 1
End If
ElseIf Z >= "A" And Z <= "Z" Then
Z = Chr(Asc(Z) + 32)
End If
Y = Y & Z
Next i
Text2.Text = Y
End Sub