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为防止机密通知被盗，某公司制定了网上发通知的加密要求：
（1）通知中包含的空格，标点符号等按原格式输出
（2）通知中涉及到字母的内容，所发文件的英语单词全部都是倒序的。如：This is a dog! 通知显示内容为： sihT si a god!
（3）通知中涉及到数字的内容， 把本组数字的最后一位移动到第一位,例如原文为 1234，通知显示内容为：4123
小王编写了一个VB程序，实现加密功能，在文本框 Text1中输入原文，单击“加密”按钮Command1 后，在文本框Text2中显示加密后的密文。程序运行界面如图所示。

实现上述功能的VB程序如下，请回答下列问题：
（1）若要修改按钮 Command1 上显示的文字，应修改的属性名是_____________（单选，填字母：A.Text/B.Caption /C.List）
（2）实现上述功能的VB程序代码如下，请在划线处填入合适的代码
（3）程序中加框处代码有错，请改正
Private Sub command1_Click()
Dim s As String, ch As String, rv As String, rv1 As String
Dim i As Integer, j As Integer, k As Integer
s = Text1.Text
rv = ""
i = 1
Do While True

ch = Mid(s, i, 1)

Do While __________ And i <= Len(s)

rv = rv + ch

i = i + 1

ch = Mid(s, i, 1)

Loop

j = i

ch =_______①_________

Do While sz(ch) And j <= Len(s)

j = j + 1

If j > Len(s) Then Exit Do

ch = Mid(s, j, 1)

Loop

rv1 = ""

rv1 = Mid(s, j - 1, 1) + Mid(s, i, j - i - 1)

rv = rv + rv1

i =_______②_______

If i > Len(s) Then Exit Do

Do While zf(ch) And j <= Len(s)

j = j + 1

If j > Len(s) Then Exit Do

ch = Mid(s, j, 1)

Loop

rv1 = ""

For k = i - 1 To j - 1

rv1 = Mid(s, k, 1) + rv1

Next k

rv = rv + rv1

If j <= Len(s) Then rv = rv + Mid(s, j, 1)

i = j + 1

If i > Len(s) Then Exit Do

Loop
Text2.Text = rv
End Sub
Function zf(s As String) As Boolean

zf = False

If s >= "A" And s <= "Z" Or s >= "a" And s <= "z" Then

zf = True

End If

End Function
Function sz(s As String) As Boolean

sz = False

If __________③____________Then

sz = True

End If

End Function