n = 0

m = 0

For i = 1 To 100

If Rnd > 0．5 Then

     n = n + 1

  Else

     m = m + 1

Next i

……

小金仔细分析该程序段后，发现其中缺少了(   )

    For i= 1 To 6

       a(i)=i+1

    Next i

该程序段运行后数组元素a(3)的值是：（   ）

实现上述功能的VB程序如下，请在划线处填入合适代码。

Private Sub Command1_Click()

  Dim i As Integer, n As Integer

  Dim x As Single, y As Single, x1 As Single, y1 As Single

  Dim d As Single, min As Single

  Dim s As String, t As String

  s = Text1.Text:   x = 25: y = 35                       'A点坐标

  n = 0: min = -1: t = ""

  For i = 1 To {#blank#}1{#/blank#}

    If Mid(s, i, 1) = "," Then

      n = n + 1

      If {#blank#}2{#/blank#} Then

         x1 = Val(t)

      Else

         y1 = Val(t)

         d = {#blank#}3{#/blank#}

         If min = -1 Then min = d

         If d < min Then min = d

      End If

      t = ""

    Else

      t = t + Mid(s, i, 1)

    End If

  Next i

  Label3.Caption = Str(min)

End Sub

Dim a(0 To 9) As Integer, t as Long

t=Val(Text1.Text)

Do While t<>0

 a(t Mod 10) = 1

 t = t \ 10

Loop

For i = 0 To 9

 x = x + a(i)

Next i

Text1中输入10242048，则程序执行后x的值为（  ）

For i=1To n＼2   

    k=i

        If a(j) <a(k) Then k=j

    Next j

    If i<>k Then

        t=a(i)：a(i)=a(k)：a(k)=t

    End If

    If  Then

        t=a(j)：a(j)=a(j+1)：a(j+1)=t

      End If

    Next j

Next i

上述程序中方框处可选语句或表达式有：

①For j=i+1 To n-i+ 1    ②For j=i+1 To n-i

③a(j)<a(j+1) ④a(j)>a(j+1)

则(1)、(2)、(3)处语句依次是（  ）